The act by which a State having previously ratified a Convention announces its intention to terminate its obligations arising from that ratification. Denunciation requires a formal instrument communicated to the ILO Director-General for registration. The conditions concerning the form and content of such an instrument are the same as those governing ratification. Accordingly, an instrument of denunciation must be signed by a person having the power to bind the State in external relations, such as the Head of State, the Prime Minister, the Minister of Foreign Affairs or the Minister of Labour.

Conventions usually provide that denunciation is permitted within a one-year interval – known as the ‘denunciation window’ – from the expiration of successive periods of ten (or, less frequently, five) years from the date on which these Conventions first came into force. A distinction is often made between ‘genuine’ or ‘pure’ denunciations, which involve the unilateral termination of the acceptance of the obligations of a Convention without the simultaneous acceptance of any related obligations, and ‘automatic’ denunciations, which are the direct consequence of the ratification of more up-to-date Conventions on the same subject and in accordance with the explicit provisions to that effect of the revised Conventions. Pure denunciations are far less common than automatic ones. In the last ten years, for instance, there have been 698 ipso jure denunciations due to ratification of more up-to-date Conventions and only 40 pure denunciations for reasons unrelated to the ratification of more up-to-date Conventions.

The Governing Body has advised that, as a general principle, when a denunciation of a ratified Convention is contemplated, it is desirable for the government to fully consult the representative organizations of employers and workers. Denunciations take effect in accordance with the final provisions of each Convention, usually one year after they are registered by the Director-General. Every denunciation registered by the Director-General is notified to the UN Secretary-General.