The International Court of Justice was established by the Charter of the United Nations, which provides that all Member States of the United Nations are ipso facto parties to the Court's Statute. The composition and functioning of the Court are organized by this Statute, and by the Rules of the Court which are drawn up by the Court itself.
Since October 2001, the Court has also issued Practice Directions for use by States appearing before it.
The Charter of the United Nations signed at San Francisco on 26 June 1945 is the constituent treaty of the United Nations. It is as well one of the constitutional texts of the International Court of Justice which was brought into being by the Charter.
The Charter deals with the Court in Article 7, paragraph 1, Article 36, paragraph 3, and Articles 92-96, which form Chapter XIV.
The Statute of the International Court of Justice is annexed to the Charter of the United Nations, of which it forms an integral part. The main object of the Statute is to organize the composition and the functioning of the Court.
The Statute can be amended only in the same way as the Charter, i.e., by a two-thirds majority vote in the General Assembly and ratification by two-thirds of the States (Art 69).
Should the ICJ consider it desirable for its Statute to be amended, it must submit a proposal to this effect to the General Assembly by means of a written communication addressed to the Secretary-General of the United Nations (Art 70). However, there has hitherto been no amendment of the Statute of the Court.
Article 30 of the Statute of the International Court of Justice provides that "the Court shall frame rules for carrying out its functions". These Rules are intended to supplement the general rules set forth in the Statute and to make detailed provision for the steps to be taken to comply with them.
The Court first adopted in October 2001 Practice Directions for use by States appearing before it. Practice Directions involve no alteration to the Rules of Court, but are additional hereto. They are the result of the Court’s ongoing review of its working methods. Any amendments to the Practice Directions, following their adoption by the Court, are now posted on the Court’s website and published in the Court’s Yearbook, with a note of any temporal reservations relating to their applicability.
In addition to the Statute and the Rules of the Court, some sides of the activities of the Court are run by other legal documents adopted by the Court, by the United Nations or concluded by the Court with the host country.