The different ILO bodies, the functioning of the General Conference, and the adoption and application of international labour standards are governed by the Constitution.
The original ILO Constitution formed Part XIII of the Treaty of Versailles (1919). Since that date it has been amended on six occasions, and has become a separate instrument. In 1944, the General Conference adopted the Declaration of Philadelphia, which restated the fundamental aims and purposes of the ILO. The Declaration is annexed to and forms an integral part of the Constitution.