How did sociology develop in the Catholic world between 1952 and 1966? What role did Bishop Manuel Larraín play in the development of the sociology of religion in Chile? How was the sociology of religion articulated with theology in the 1960s? These are some of the questions that this contribution aims to address. The reception in Chile of the Social Doctrine of the Church and the evolution of social Catholicism, its intellectuals and spirituals, allow us to discover the role of transnational movements in the development of the social sciences within the Catholic Church. At the end of Pius XII's pontificate (1958), Latin American countries played a key role in this process, in particular through the foundation of CELAM (Conferencia Episcopal de América Latina) and the impetus given to FERES (Federación Internacional de Investigaciones Socio religiosas). The global geopolitical context, marked by the Cold War, the threat of communism and Protestantism, fundamentally influenced the development of a discipline that began to be seen, at least from Manuel Larraín's point of view, as a theological place. The present contribution, using as a basis the unpublished correspondence of Manuel Larraín, seeks to explore the relationship of the bishop of Talca with the sociology of religion, and above all, the enormous impulse he gave to it within CELAM and the Chilean Church, having an important place in the elaboration of the Pastoral Constitution Gaudium et Spes of the Vatican Council II. To this end, we will deal with the way in which the sociology of religion is conceived at the service of pastoral planning; the problem of underdevelopment and Christian sociology; François Houtart and his support for FERES; the link between socio-religious studies and theology in the drafting of Gaudium et Spes.