This article discusses the origins of ‘misión integral’ or integral mission, a term coined by the Ecuadorian theologian C. René Padilla (b. 1932). As the first critical study of Padilla, it argues that the origins of ‘misión integral’ are to be found within a cluster of political and social forces that were reshaping post-war Latin America: rural-urban migration, the resulting complications of urbanisation and the rapid expansion of the universities, where Marxist ideas of revolutionary change were of growing appeal to students. This article relies on interviews with many of the leading personalities involved, together with personal papers, archival research and Latin American census data.