The Statute begins with Article 1 proclaiming: "The international Court of Justice established by the Charter of the United Nations as the principal judicial organ of the United Nations shall be constituted and shall function in accordance with the provisions of the present Statute.

Article 38.1 lists sources that the court may apply to decide a case, including: treaties, customary international law, general principles of law, and (as subsidiary means) judicial decisions and academic writing.

These sources are qualified by Article 59 which states that ICJ decisions are binding only to the parties in that case, and Article 38.2 which allows the court to decide a case ex aequo et bono if the parties agree thereto.

Under Article 93(2) of the UN Charter, states which are not a member of the UN may become a party to the Statute, subject to the recommendation of the United Nations Security Council and approval of the United Nations General Assembly.

Switzerland (1948-2002), Liechtenstein (1950-1990), San Marino (1954-1992), Japan (1954-1956), and Nauru (1988-1999) were all parties to the Statute prior to becoming UN member states.