In the late 1940s, state socialist governments proclaimed that commercial sex did not exist under socialism. At the same time, they were enthusiastic participants in the drafting of a new UN Convention for the Suppression of the Traffic in Persons and the Exploitation of the Prostitution of Others. This article explores state socialist involvement in the global moral reform drive accompanying the 1949 Convention. It traces the ideological coherence between Socialist Bloc and ‘Western’ delegations on the desirability of prostitution’s abolition. Conversely, it highlights splits on issues of jurisdiction, manifesting in the Soviet call for the eradication of the draft Convention’s ‘colonial clause’, which allowed states to adhere to or withdraw from international instruments on behalf of ‘non-self-governing territories’. We argue that critiques of the colonial clause discursively stitched together global moral reform and opposition to imperialism, according socialist and newly decolonized delegations an ideological win in the early Cold War.