In this paper, we study the ideological bases of mental hygiene, understood as racial and moral hygiene, during the first years of Franco's regime and their evolution until 1960. First, we discuss the conceptualization of mental hygiene in the 1940s and its role as a tool for the legitimization of dictatorship, revealing the involvement of orthodox Catholicism and its links with moral and racial hygiene. Second, we assess the transformation of mental hygiene during the 1950s towards modernization and a stronger linkage with the dominant trends of contemporary psychiatry without ever leaving the ideological background of Catholicism. For this purpose, we will focus on analysis of the activities of the Mental Hygiene Week held in Barcelona in 1954 and on the creation in 1955 of the National Board of Psychiatric Care, which took on mental hygiene as one of its functions. This paper shows the close relationship of mental hygiene during the early years of Francoism with the political principles of the Dictatorship. The 1940s witnessed the deployment of a harsh discourse in which mental hygiene was a tool for the (moral and spiritual) education of the Spanish people in the political principles of the "New State", pathologizing political dissent and ideologically purifying the country. In the 1950s, Francoist mental hygiene underwent a process of aggiornamento marked by international political events following the defeat of fascism in World War II, advancing a project for (authoritarian) modernization in an international context already directed towards mental health.