The formal revision of a Convention, whether in whole or in part, may involve the adoption of a new self-contained Convention or a Protocol. For instance, the Protection of Workers’ Claims (Employer’s Insolvency) Convention, 1992 (No. 173) revises article 11 of the Protection of Wages Convention, 1949 (No. 95) whereas the MLC, 2006 revises and replaces 37 maritime labour Conventions. The intention to revise an earlier Convention is explicitly or implicitly stated in the title (e.g. Convention No. 185), preamble (e.g. Convention No. 96) or operative provisions (e.g. Convention Nos. 181 and 183) of the later Convention. In some cases (e.g. Convention No. 131), a Convention specifies that it may not be regarded as revising any existing Convention. 

The Standing Orders of the Conference and the Governing Body include specific provisions applicable to revision of standards. In practice, the revision of an instrument is placed as an item on the agenda of the Conference and may result in the adoption of a revised instrument through double or single discussion. Unless a new Convention revising an earlier one provides otherwise, its ratification involves the automatic denunciation of the earlier Convention while the earlier Convention ceases to be open to ratification as from the date when the new Convention comes into force. The revision of Recommendations has lesser consequences. When a Recommendation expressly provides that it ‘revises’ or ‘supersedes’ an earlier one (e.g. the Human Resources Development Recommendation, 2005 (No. 195) and the Employment and Decent Work for Peace and Resilience Recommendation, 2017 (No. 205), the earlier instrument is deemed to have been ‘juridically replaced’. When a new Recommendation overrides the provisions of an earlier instrument without making explicit reference to revision, the earlier instrument is considered ‘de facto replaced’.

By revision of standards, it is sometimes understood the work of ad hoc working groups set up with a view to evaluating the continued relevance of existing instruments and identifying the needs for formal revision. As of the mid 1970s, the Governing Body established three such ad hoc working groups - all best known after the names of their respective chairpersons. The first Ventejol Working Party on International Labour Standards, was established in 1977. It concluded its work in 1979 and led to the adoption by the Governing Body of a classification of existing standards, including instruments to be revised. A second Ventejol Working Party on International Labour Standards, was established in 1984. It concluded its work in 1987 and led to the adoption by the Governing Body of a revised classification of existing instruments. The Cartier Working Party on Policy concerning the Revision of International Labour Standards was established in 1995 and concluded its work in March 2002. It carried out a case-by-case examination of the instruments adopted prior to 1985 with the exception of the fundamental and governance Conventions. The recommendations of the Working Party resulted in the decision by the Governing Body that 22 Conventions and 15 Recommendations should be revised, 71 Conventions and 71 Recommendations should be promoted and that 60 Conventions and 68 Recommendations were outdated.