1. The General Assembly of the United Nations, having considered chapter II of the report of the International Law Commission on the work of its eighteenth session, which contained final draft articles and commentaries on the law of treaties (A/6309/Rev. 1), decided, by its resolution 2166 (XXI) of 5 December 1966, to convene an international conference of plenipotentiaries to consider the law of treaties and to embody the results of its work in an international convention and such other instruments as it might deem appropriate. By the same resolution, the General Assembly requested the Secretary-General to convoke the first session of the conference early in 1968 and the second session early in 1969.

Subsequently, the General Assembly, noting that an invitation had been extended by the Austrian Government to hold both sessions of the conference at Vienna, decided, by resolution 2287 (XXII) of 6 December 1967, that the first session should be convened at Vienna in March 1968. At its fifth meeting, held on 24 May 1968, at the conclusion of the first session, the Conference adopted a resolution requesting the Secretary-General to make all the necessary arrangements for the Conference to hold its second session at Vienna from 9 April to 21 May 1969.

2. The first session of the United Nations Conference on the Law of Treaties was held at the Neue Hofburg, Vienna, from 26 March to 24 May 1968. The second session of the Conference was also held at the Neue Hofburg, from 9 April tot 22 May 1969.

3. One hundred and three States were represented at the first session of the Conference, and one hundred and ten States at the second session, as follows: Afghanistan, Algeria, Argentina, Australia, Austria, Barbados (second session only), Belgium, Bolivia, Brazil, Bulgaria, Burma (second session only), Byelorussian Soviet Socialist Republic, Cambodia, Cameroon (second session only), Canada, Central African Republic, Ceylon, Chile, China, Colombia, Congo (Brazzaville), Congo (Democratic Republic of), Costa Rica, Cuba, Cyprus, Czechoslovakia, Dahomey, Denmark, Dominican Republic, Ecuador, El Salvador (second session only), Ethiopia, Federal Republic of Germany, Finland, France, Gabon, Ghana, Greece, Guatemala, Guinea (first session only), Guyana, Holy See, Honduras, Hungary, Iceland (second session only), India, Indonesia, Iran, Iraq, Ireland, Israel, Italy, Ivory Coast, Jamaica, Japan, Kenya, Kuwait, Lebanon, Lesotho (second session only), Liberia, Libya (second session only), Liechtenstein, Luxembourg (second session only), Madagascar, Malaysia, Mali (first session only), Malta (second session only), Mauritania (first session only), Mauritius, Mexico, Monaco, Mongolia, Morocco, Nepal, Netherlands, New Zealand, Nigeria, Norway, Pakistan, Panama (second session only), Peru, Philippines, Poland, Portugal, Republic of Korea, Republic of Viet-Nam, Romania, San Marino, Saudi Arabia, Senegal, Sierra Leone, Singapore, Somalia (first session only), South Africa, Spain, Sudan (second session only), Sweden, Switzerland, Syria, Thailand, Trinidad and Tobago, Tunisia, Turkey, Uganda (second session only), Ukrainian Soviet Socialist Republic, Union of Soviet Socialist Republics, United Arab Republic, United Kingdom of Great Britain and Northern Ireland, United Republic of Tanzania, United States of America, Uruguay, Venezuela, Yemen (first session only), Yugoslavia and Zambia.

4. The General Assembly invited the specialized agencies and interested intergovernmental organizations to send observers to the Conference. The following specialized agencies and interested intergovernmental organizations accepted this invitation:

Specialized and related agencies

International Labour Organisation

Food and Agriculture Organization of the United Nations

United Nations Educational, Scientific and Cultural Organization

International Civil Aviation Organization

International Bank for Reconstruction and Development and International Development Association

International Monetary Fund

World Health Organization

Universal Postal Union

Inter-Governmental Maritime Consultative Organization

International Atomic Energy Agency

Intergovernmental organizations

Asian-African Legal Consultative Committee

United International Bureaux for the Protection of Intellectual Property

Council of Europe

General Agreement on Tariffs and Trade

League of Arab States

5. The Conference elected Mr. Roberto Ago (Italy) as President.

6. The Conference elected as Vice-Presidents the representatives of the following States: Afghanistan, Algeria, Austria, Chile, China, Ethiopia, Finland, France, Guatemala (for 1969), Guinea, Hungary, India, Mexico, Peru, Philippines, Romania, Sierra Leone, Spain (for 1968), Union of Soviet Socialist Republics, United Arab Republic, United Kingdom of Great Britain and Northern Ireland, United States of America, Venezuela and Yugoslavia.

7. The following committees were set up by the Conference:

General Committee

Chairmain: | The President of the Conference

Members: | The President and Vice-Presidents of the Conference, the Chairman of the Committee of the Whole and the Chairman of the Drafting Committee.

Committee of the Whole

Chairman: | Mr. Taslim Olawale Elias (Nigeria)

Vice-Chairman: | Mr. Josef Šmejkal (Czechoslovakia)

Rapporteur: | Mr. Eduardo Jiménez de Aréchaga (Uruguay)

Drafting Committee

Chairman: | Mr. Mustafa Kamil Yasseen (Iraq)

Members: | Argentina, China, Congo (Brazzaville), France, Ghana, Japan, Kenya, Netherlands, Poland, Sweden, Union of Soviet Socialist Republics, United Kingdom of Great Britain and Northern Ireland, United States of America and, ex-officio in accordance with rule 48 of the Rules of Procedure, Mr. Eduardo Jiménez de Aréchaga (Uruguay), Rapporteur of the Committee of the Whole.

Credentials Committee

Chairman: | Mr. Eduardo Suárez (Mexico)

Members: | Ceylon, Dominican Republic, Japan, Madagascar, Mali (first session), Mexico, Switzerland, Union of Soviet Socialist Republics, United Republic of Tanzania (second session) and United States of America.

8. Sir Humphrey Waldock, Special Rapporteur of the International Law Commission on the law of treaties, acted as Expert Consultant.

9. The Secretary-General of the United Nations was represented by Mr. C. A. Stavropoulos, Under-Secretary-General, The Legal Counsel. Mr. A. P. Movchan, Director of the Codification Division of the Office of Legal Affairs of the United Nations, acted as Executive Secretary.

10. The General Assembly, by its resolution 2166 (XXI) convening the Conference, referred to the Conference, as the basis for its consideration of the law of treaties, chapter II of the report of the International Law Commission on the work of its eighteenth session, containing the text of the final draft articles and commentaries on the law of treaties adopted by the Commission at that session (A/6309/ Rev. 1).

11. The Conference also had before it the following documentation:

(a) the relevant records of the General Assembly and of the International Law Commission relating to the law of treaties;

(b) comments and amendments relating to the final draft articles on the law of treaties submitted by Governments in 1968 in advance of the Conference in accordance with General Assembly resolution 2287 (XXII) (A/CONF. 39/6 and Add. 1-2);

(c) written statements submitted by specialized agencies and intergovernmental bodies invited to send observers to the Conference (A/CONF. 39/7 and Add. 1-2 and Add. 1/ Corr. 1);

(d) a selected bibliography on the law of treaties (A/CONF. 39/4), an analytical compilation of comments and observations made in 1966 and 1967 on the final draft articles on the law of treaties (A/CONF. 39/5, Vols. I and II), standard final clauses (A/CONF. 39/L. 1), a guide to the draft articles on the law of treaties (A/C.6/376) and other pertinent documentation prepared by the Secretariat of the United Nations.