The present position in regard to membership of the Security Council is set out in Article 23 of the UN Charter as amended; and the geographical distribution of elected seats on the Council is determined in accordance with a UN General Assembly resolution of 1963.
Under Article 23 of the UN Charter the Security Council has a membership of 15 of whom five are permanent members and ten are elected for two year terms. Paragraph 1 of that Article provides that:
The Security Council shall consist of fifteen Members of the United Nations. The Republic of China, France, the Union of Soviet Socialist Republics, the United Kingdom of Great Britain and Northern Ireland and the United States of America shall be permanent members of the Security Council. The General Assembly shall elect ten other members of the United Nations to be non-permanent members of the Security Council, due regard being specially paid, in the first instance to the contribution of members of the United Nations to the maintenance of international peace and security and to the other purposes of the organisation and also to equitable geographical distribution.
The Charter as adopted in 1945 had provided for a membership of 11 of whom six were elected but Article 23 was amended in 1963 so as to expand the membership of the Council to the present level of 15.