Vienna Convention on the Law of Treaties between States and
International Organizations or between International Organizations

Vienna, 21 March 1986
  •  Introductory Note 
  •  Procedural History 
  •  Documents 
  •  Status 
  •  Photo 
By Karl Zemanek
Emeritus Professor, University of Vienna
Vice-Chairman of the Austrian Delegation to the United Nations Conference on the Law of Treaties

العربيةArabic 中文Chinese EnglishEnglish Français French РусскийRussian  Español Spanish

Historical Context

After 1945, the United Nations and its specialized agencies, followed by other international organizations, concluded an increasing number of treaties with States (e.g., agreements on privileges and immunities or headquarter agreements) or between themselves (e.g., cooperation agreements) and thereby built up a fair amount of practice. Scholars created different theories to identify the legal basis of these treaties in international law and the International Court of Justice used the practice for affirming the international legal personality of the United Nations in its Advisory Opinion on Reparation for Injuries Suffered in the Service of the United Nations (I.C.J. Reports 1949, pp. 174-188, at 179). But no generally shared opinio juris evolved. That became evident during the work of the International Law Commission on the codification of the law of treaties: it first included (1950), but later excluded (1962), treaties concluded by international organizations from its draft articles on the law of treaties (see Yearbook of the International Law Commission, 1950, vol. II, part VI, chapter I, and ibid., 1962, vol. II, chapter II).

After an unsuccessful attempt at the United Nations Conference on the Law of Treaties to reintroduce such treaties into that Convention, the Conference recommended that the General Assembly entrust the International Law Commission with the preparation of a separate set of draft articles (see Final Act of the Conference, resolution relating to article 1 of the Vienna Convention on the Law of Treaties), which the Commission submitted in 1982.

Significant Developments in the Negotiating History

Thereupon, in 1986, the General Assembly decided to hold a conference in Vienna to adopt the draft articles as a convention. In view of a subject on which particularly the East and the West had strong opposing views, the Assembly took an active part in the preparation of the Conference. It had two main aims: to avoid possible discrepancies between parallel provisions in the 1969 Vienna Convention on the Law of Treaties and the new convention; and to ensure that the specific provisions concerning international organizations would be acceptable to the greatest possible number of participants.

With that in mind, the Assembly transmitted to the Conference a consensus list of articles which had to be considered in full, while all other articles were only to be reviewed for consequential drafting adaptations. The Assembly further adopted draft rules of procedure for the Conference which made the adoption of articles by vote the exception, as voting on codification texts had lately produced unsatisfactory results. In fact, all substantive articles were adopted without a vote by the Conference and only the settlement of disputes procedure, the final clauses and the Convention as a whole were voted on.

Summary of Key Provisions

The first 72 articles of the Convention retain mutatis mutandis the text of the relevant articles of the 1969 Vienna Convention on the Law of Treaties. This was achieved by using new terms where none had existed for the transactions of international organizations, such as “act of formal confirmation” (article 2, para. 1(b bis) to correspond to the ratification by States, and by adopting appropriate additional paragraphs referring to international organizations to otherwise unchanged articles.

On a few fundamental questions, however, opinions had been for a long time, and were still, divided. This applied, in particular, to the unsettled question of the source of an organization’s treaty-making capacity. Socialist States asserted that international organizations possessed international legal personality only if it had been conferred upon them by the founding States and treaty-making capacity only if it was explicitly provided for in their constituent instruments. That view was opposed by the great majority of other States and their position inspired the solution adopted by the Conference.

The Convention uses the functional approach from the International Court of Justice’s Advisory Opinion Certain Expenses of the United Nations (I.C.J. Reports 1962, pp. 151-180, at 167-168) and states in its preamble that “international organizations possess the capacity to conclude treaties which is necessary for the exercise of their functions and fulfilment of their purposes”. Key provisions determining the scope of an organization’s capacity to conclude treaties are in article 6 of the Convention, which provides that “[t]he capacity of an international organization to conclude treaties is governed by the rules of that organization”, and the definition in article 2, paragraph 1 (j), which includes the “established practice” among the rules of the organization. The preambular paragraph, which affirms that “the practice of international organizations in concluding treaties with States or between themselves should be in accordance with their constituent instruments”, gives the organization sufficient room to develop its practice by pursuing the purposes which are enshrined in its constituent instrument. Together, these provisions establish that the scope of an organization’s treaty-making capacity is determined by its constituent instrument and rules, but suggest that its international personality derives from general international law. It is, however, important to note that the Convention uses the term “rules of the organization” in two senses. In some articles (e.g., articles 6 or 39, para. 2) the term indicates a qualifying international law limitation, whereas in other articles (article 27, para. 2, and 46, para. 2) the rules are treated as internal law in the same manner as the internal law of States.

The draft articles of the International Law Commission did not contain any provision to regulate the relation between the 1969 Convention and the new Convention. Hence, it might have been uncertain which of them would apply to the relations between States under a multilateral treaty to which international organizations were also parties. Since it could not be predicted, moreover, when the new Convention would come into force and for which States, the Conference felt the need of regulation to avoid confusion. Article 73 now provides that in respect of multilateral treaties to which international organizations are also parties, it is the 1969 Convention that continues to apply between the States parties of the multilateral treaty.

The settlement of disputes procedure in article 66 and the annex to the Convention, though it follows as far as possible the model of the 1969 Convention, is highly complex in respect of disputes concerning jus cogens. Since international organizations have no standing before the International Court of Justice in contentious proceedings, the device of advisory opinions of the Court, which, under the Convention, are accepted as binding by the parties to the dispute, was employed. However, not all international organizations are authorized to request advisory opinions of the Court; such organizations are advised to do it through a Member State of the United Nations. Should the request not be granted, the dispute may be submitted by any of the parties to the dispute to arbitration in accordance with the provisions of the annex. Recourse to arbitration instead of proceedings before the International Court of Justice is also possible when all the parties to the dispute so agree.

The Conference could not resolve the question of the rights and/or obligations which might arise for States members of an international organization from a treaty to which that organization is a party. The Convention contains only a saving-clause (article 74, para. 3). The discussion on the International Law Commission’s proposed article 36 bis (see Yearbook of the International Law Commission, 1982, vol. II, Part Two, p. 43) at the Conference had made it obvious that the relevant situations were too varied to be covered by a single uniform provision.

Influence of the Instrument on Subsequent Developments

The Convention is not yet in force (as of 18 November 2008). It needs 35 ratifications or accessions by States to do so, (article 85), which are the only ones that count for entry into force purposes, and has as yet only obtained 28. 12 international organizations, including the United Nations, have either confirmed their signature or acceded to the Convention. Nevertheless, as happens with other codified international legal rules, the Convention is, regardless of its formal status, generally accepted as the applicable law and is widely used as a handy written guide in practice.

Related Materials

A. Legal Instruments

Vienna Convention on the Law of Treaties, Vienna, 23 May 1969, United Nations, Treaty Series, vol. 1155, p. 331.

B. Jurisprudence

International Court of Justice, Reparation for injuries suffered in the service of the United Nations, Advisory Opinion, I.C.J. Reports 1949, p. 174.

International Court of Justice, Certain Expenses of the United Nations (Article 17, paragraph 2, of the Charter), Advisory Opinion of 20 July 1962: I.C.J. Reports 1962, p. 151.

C. Documents

Yearbook of the International Law Commission 1950, vol. II ( A/CN.3/34), part VI, chapter I, p. 380.

Yearbook of the International Law Commission 1962, vol. II (A/CN.4/148), p. 159.

Official Records of the United Nations Conference on the Law of Treaties, First and second sessions, Documents of the Conference (A/CONF.39/11/Add.2), Final Act of the United Nations Conference on the Law of Treaties, Annex, p. 281.

Yearbook of the International Law Commission 1982, vol. II (A/CN.4/SER.A/1982/Add.1 (Part 2)), Part Two, chapter II, p. 9.

D. Doctrine

G. Gaja, “A ‘New’ Vienna Convention on Treaties Between States and International Organizations or Between International Organizations: A Critical Commentary”, British Yearbook of International Law, vol. 58, 1987, pp. 253-269.

M. Hayashi, “The Dispute Settlement Clause of the 1986 Vienna Convention on the Law of Treaties”, New York University Journal of International Law and Politics, vol. 19, 1987, pp. 327-356.

H. Isak & G. Loibl, “United Nations Conference on the Law of Treaties Between States and International Organizations or Between International Organizations”, Österreichische Zeitschrift für öffentliches Recht und Völkerrecht, vol. 38, 1987, pp. 49-78.

Ph. Manin, “La Convention de Vienne sur le droit des traités entre états et organisations internationales ou entre organisations internationales”, Annuaire Francais de Droit International, vol. 32, 1986, pp. 474-494.

P. K. Menon, The Law of Treaties Between States and International Organizations, Lewiston, New York, Edwin Mellen Press, 1992.

G. E. do Nascimento e Silva, “The 1986 Vienna Convention and the Treaty-Making Power of International Organizations”, German Yearbook of International Law, vol. 29, 1986, pp. 68-85.

Sh. Rosenne, Developments in the Law of Treaties 1945-1986, Cambridge [England]; New York: Cambridge University Press, 1989, pp. 10-32.

T. Treves, “Innovations dans la technique de codification du droit international. La préparation de la Conférence de Vienne sur les traités passés par les organisations internationales”, Annuaire Francais de Droit International, vol. 32, 1986, pp. 474-494.

K. Zemanek, “The United Nations Conference on the Law of Treaties Between States and International Organizations or Between International Organizations: The Unrecorded History of its General Agreement”, in: K. H. Böckstigel et al. (eds.), Law of Nations, Law of International Organizations, World Economic Law: Liber Amicorum Ignaz Seidl-Hohenveldern, Cologne, Heymanns, 1988, pp. 665-679.

K. Zemanek, “Agreements Concluded by International Organizations and the Vienna Convention on the Law of Treaties”, University of Toledo Law Review, vol. 89, 1971, pp. 145-183.

K. Zemanek (ed.), Agreements of International Organizations and the Vienna Convention on the Law of Treaties, Vienna, Springer Verlag, 1971 (Österreichische Zeitschrift für öffentliches Recht, Supplementum 1).


العربية Arabic 中文  English English Français French Русский Russian Español Spanish

The United Nations Conference on the Law of Treaties, held in 1969 at Vienna, adopted a resolution entitled “Resolution relating to article 1 of the Vienna Convention on the Law of Treaties”, annexed to the Final Act, recommending that the General Assembly should refer to the Commission the study of the question of treaties concluded between States and international organizations or between two or more international organizations. Acting on this recommendation, the General Assembly, in resolution 2501 (XXIV) of 12 November 1969, recommended that the International Law Commission should study the question, in consultation with the principal international organizations.

26 April 1971, Twenty-third Session of the International Law Commission, Palais des Nations, Geneva: Mr. Paul Reuter (left), Special Rapporteur on the Question of treaties concluded between States and international organizations or between two or more international organizations and Mr. S. Rosenne sitting at his left, at the opening meeting. At its twenty-second session, in 1970, the Commission included this question in its programme of work and set up a subcommittee to consider the preliminary problems involved in the study of the topic. The subcommittee’s report (A/CN.4/L.155), as adopted by the Commission, requested the Secretariat to undertake certain preparatory work, in particular as regards United Nations practice, and asked the Chairman of the subcommittee to submit to members of the subcommittee a questionnaire concerning the method of treating the topic and its scope. At the Commission’s twenty-third session, in 1971, the subcommittee submitted to the Commission a report (A/CN.4/250) containing a summary of the views expressed by members of the subcommittee in reply to the questionnaire prepared by its Chairman, and recommendations to the Commission, in particular to appoint a Special Rapporteur for the topic and confirm the request addressed to the Secretary-General concerning certain preparatory work. The Commission considered the report and adopted it without change. At the same session, the Commission appointed Paul Reuter as Special Rapporteur for the topic.

The Commission considered the topic from its twenty-fifth to twenty-seventh and from its twenty-ninth to thirty-fourth sessions, from 1973 to 1975 and from 1977 to 1982, respectively. In connection with its consideration of the topic, the Commission had before it the reports of the Special Rapporteur (referred to in the “Documents” section), information provided by Governments and international organizations (A/CN.4/339 and Add.1–8; A/CN.4/350 and Add.1–6, Add.6/Corr.1 and Add.7–11) as well as documents prepared by the Secretariat (A/CN.4/L.161 and Add.1 and 2; A/CN.4/277 and A/CN.4/281).

At its twenty-fifth session, in 1973, the Commission requested the Special Rapporteur to begin the preparation of a set of draft articles on the basis of his first two reports and the comments made during that session. At its twenty-sixth session, in 1974, the Commission began the first reading of the draft articles, which was completed at its thirty-second session, in 1980. In accordance with the decision taken by the Commission at its thirtieth session, in 1978, the Commission, upon provisional adoption of certain sets of draft articles, transmitted them to Governments and principal international organizations for comments and observations, before the draft as a whole was adopted on the first reading. That procedure was seen as making it possible for the Commission to undertake the second reading without much delay.

The General Assembly, in resolution 35/163 of 15 December 1980, invited the Commission to commence the second reading of the draft articles.

The Commission proceeded with the second reading of the draft articles at its thirty-third and thirty-fourth sessions, in 1981 and 1982, respectively, in accordance with the General Assembly recommendation contained in resolution 36/114 of 10 December 1981. At the latter session, the Commission adopted the final text of the draft articles, with commentaries, on the law of treaties between States and international organizations or between international organizations, and submitted it to the General Assembly with the recommendation that the Assembly convoke a conference to conclude a convention on the subject under article 23, subparagraph 1 (d) of its Statute.

By resolution 37/112 of 16 December 1982, the General Assembly decided that an international convention should be concluded on the basis of the draft articles adopted by the Commission. In addition, the Assembly invited States and the principal international organizations to submit comments on the final draft as well as on other questions, such as the participation of international organizations in the conference and the solution of the problem of how international organizations would be associated with the convention.

At its thirty-eighth session, the General Assembly, by resolution 38/139 of 19 December 1983, decided that the appropriate forum for the final consideration of the draft articles was a conference of plenipotentiaries, to be convened not earlier than 1985. It also appealed to potential participants in the Conference to undertake consultations on the draft articles and related questions prior to the thirty-ninth session of the Assembly, in order to facilitate the successful conclusion of the work of the Conference. The following year the General Assembly, by resolution 39/86 of 13 December 1984, decided that the United Nations Conference on the Law of Treaties between States and International Organizations or between International Organizations would be held at Vienna from 18 February to 21 March 1986 and referred to the Conference as the basic proposal for its consideration the final set of draft articles adopted by the Commission at its thirty-fourth session, in 1982. It also appealed to participants in the Conference to organize consultations, primarily on the organization and methods of work of the Conference, including rules of procedure, and on major issues of substance, including final clauses and settlement of disputes, prior to the convening of the Conference in order to facilitate a successful conclusion of its work through the promotion of general agreement.

Informal consultations were held between 18 March and 1 May and between 8 and 12 July 1985 (A/C.6/40/10). By resolution 40/76 of 11 December 1985, the General Assembly considered that those informal consultations proved useful in enabling thorough preparation for successful conduct of the Conference. The Assembly decided to transmit to the Conference, and to recommend that it adopt, the draft rules of procedure for the Conference, worked out during the informal consultations (annex I of the resolution). Also, the Assembly decided to transmit to the Conference for its consideration and action, as appropriate, a list of draft articles of the basic proposal, for which substantive consideration was deemed necessary (annex II of the resolution). Finally, the Assembly referred to the Conference for its consideration the draft final clauses presented by the co-Chairmen of the informal consultations on which an exchange of views had been held (annex III of the resolution).

The Conference was held at Vienna from 18 February to 21 March 1986. Ninety-seven States participated in the Conference, as did also Namibia, represented by the United Nations Council for Namibia. The Palestine Liberation Organization, the African National Congress of South Africa and the Pan Africanist Congress of Azania were represented by observers. Nineteen international intergovernmental organizations, including the United Nations, were represented at the Conference.

The Conference assigned to the Committee of the Whole those draft articles of the basic proposal which required substantive consideration as well as the preparation of the preamble and the final provisions of the Convention. It referred all other draft articles of the basic proposal directly to the Drafting Committee, which was furthermore responsible for considering the draft articles referred to it by the Committee of the Whole and for coordinating and reviewing the drafting of all texts adopted, as well as for the preparation of the Final Act of the Conference.

On 20 March 1986, the Conference adopted the Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations (A/CONF.129/15). In addition, the Conference adopted five resolutions which were annexed to the Final Act of the Conference (A/CONF.129/14).

On 21 March 1986, the Convention was opened for signature, by all States, Namibia, represented by the United Nations Council for Namibia, and international organizations invited to participate in the Conference. It remained open for signature until 31 December 1986 at the Federal Ministry for Foreign Affairs of the Republic of Austria and, subsequently, until 30 June 1987 at United Nations Headquarters. The Convention is subject to ratification by States and to acts of formal confirmation by international organizations. The Convention remains open for accession by any State and by any international organization which has the capacity to conclude treaties. The Convention is not in force: it shall enter into force on the thirtieth day following the date of deposit of the thirty-fifth instrument of ratification or accession by a State.


Text of the Convention

Selected preparatory documents
(in chronological order)

General Assembly resolution 2501 (XXIV) of 12 November 1969 (Report of the International Law Commission and resolution relating to article 1 of the Vienna Convention on the Law of Treaties)

International Law Commission, Report of the Sub-Committee on Treaties concluded between States and International Organizations or between two or more International Organizations, 4 May to 10 July 1970 (A/CN.4/L.155, reproduced in Yearbook of the International Law Commission, 1970, vol. II, para. 89)

Report of the Sub-Committee on Treaties concluded between States and international organizations or between two or more International Organizations; twenty-third session of the International Law Commission, 26 April to 30 July 1971 (A/CN.4/250, 1 July 1971, reproduced in Yearbook of the International Law Commission, 1971, vol. II (Part Two))

International Law, Working paper submitted by the Secretary-General, containing a short bibliography, a historical survey of the question and a preliminary list of the relevant treaties published in the United Nations Treaty Series (A/CN.4/L.161 and Add.1 and 2, 1971)

International Law Commission, First report on the question of treaties concluded between States and International Organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/258, 3 April 1972, reproduced in Yearbook of the International Law Commission, 1972, vol. II)

International Law Commission, Second report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/271, 15 May 1972, reproduced in Yearbook of the International Law Commission,1973, vol. II)

International Law Commission, Selected bibliography on the question of treaties concluded between States and international organizations or between two or more international organizations, prepared by the Secretariat (A/CN.4/277, 15 March 1974, reproduced in Yearbook of the International Law Commission, 1974, vol. II (Part Two))

International Law Commission, Third report on treaties concluded between States and International Organizations or between two or more International Organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/279 and Corr.1, 29 March 1974, reproduced in Yearbook of the International Law Commission,1974, vol. II (Part One))

International Law Commission, Study prepared by the Secretariat, “Possibilities of participation by the United Nations in international agreements on behalf of a territory” (A/CN.4/281, 10 June 1974, reproduced in Yearbook of the International Law Commission, 1974, vol. II (Part Two))

International Law Commission, Fourth report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/285, 21 March 1975, reproduced in Yearbook of the International Law Commission, 1975, vol. II)

International Law Commission, Fifth report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/290 and Add.1, 10 February 1976, reproduced in Yearbook of the International Law Commission, 1976, vol. II (Part One))

International Law Commission, Sixth report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/298, 11 March 1977, reproduced in Yearbook of the International Law Commission, 1977, vol. II (Part One))

International Law Commission, Seventh report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/312, 1 June 1978, reproduced in Yearbook of the International Law Commission, 1978, vol. II (Part One))

International Law Commission, Eighth report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/319, 9 March 1979, reproduced in Yearbook of the International Law Commission, 1979, vol. II (Part One))

International Law Commission, Ninth report on the Question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/327, 28 February 1980, reproduced in Yearbook of the International Law Commission, 1980, vol. II (Part One))

General Assembly resolution 35/163 of 15 December 1980 (Report of the International Law Commission)

International Law Commission, Tenth report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/341 and Add.1, 3 and 6 April 1981, reproduced in Yearbook of the International Law Commission, 1981, vol. II (Part One))

International Law Commission, Comments and observations of Governments and principal international organizations on articles 1 to 60 of the draft articles on treaties concluded between States and international organizations, or between international organizations, adopted by the Commission (A/CN.4/339 and Add.1-8, reproduced in Yearbook of the International Law Commission, 1981, vol. II (Part Two), Annex II))

General Assembly resolution 36/114 of 10 December 1981 (Report of the International Law Commission)

International Law Commission, Eleventh report on the question of treaties concluded between States and international organizations or between two or more international organizations, by Mr. Paul Reuter, Special Rapporteur (A/CN.4/353, 26 March 1982, reproduced in Yearbook of the International Law Commission, 1982, vol. II (Part One))

International Law Commission, Question of treaties concluded between States and international organizations or between two or more international organizations. Comments and observations of Governments and principal international organizations on draft articles 61 to 80 and annex (A/CN.4/350 and Add.1-6, Add.6/Corr.1 and Add.7-1, reproduced in Yearbook of the International Law Commission,1982,vol. II (Part 2))

General Assembly resolution 37/112 of 16 December 1982 (Convention on the Law of Treaties between States and International Organizations or between International Organizations)

General Assembly resolution 38/139 of 19 December 1983 (United Nations Conference on the Law of Treaties between States and International Organization or between International Organizations)

General Assembly resolution 39/86 of 13 December 1984 (United Nations Conference on the Law of Treaties between States and International Organization or between International Organizations)

General Assembly resolution 40/76 of 11 December 1985 (Preparation for the United Nations Conference on the Law of Treaties between States and International Organizations or between International Organizations)

Official Records of the United Nations Conference on the Law of Treaties between States and nternational Organizations or between International Organizations, held in Vienna, from 18 February to 21 March 1986, A/CONF.129/16, Documents of the Conference vol. II, United Nations publication, Sales No. 94.V.5


The Convention is not yet in force. For the current participation status of the Convention, as well as information and relevant texts of related treaty actions, such as reservations, declarations, objections, denunciations and notifications, see: The Status of Multilateral Treaties Deposited with the Secretary-General:

The Status of Multilateral Treaties Deposited with the Secretary-General

26 April 1971, Twenty-third Session of the International Law Commission, Palais des Nations, Geneva: Mr. Paul Reuter (left), Special Rapporteur on the Question of treaties concluded between States and international organizations or between two or more international organizations and Mr. S. Rosenne sitting at his left, at the opening meeting.      
26 April 1971
Twenty-third Session of the International Law Commission, Palais des Nations, Geneva
[Read more]