Contemporary Latin America has witnessed a significant decline in Catholic religious practice, with Chile standing out for its increasing number of disaffiliated individuals who express little interest in alternative religious options. This study applies secularization theory to examine the socio-cultural shifts beginning with Chile's Catholic heritage and progressing toward widespread decatholicization. The article hypothesizes that societal and cultural changes in Chile are driving corresponding shifts in religious identities. The primary goal is to understand how and why massive Catholic disaffiliation is occurring in modern Chile. To investigate this, the study analyzes pooled cross-sectional data from the National Bicentennial Survey (2006-2023, N=33,607) through OLS regressions, focusing on age, period, and cohort effects, with an emphasis on the latter two. Catholic disaffiliation is assessed through changes in religious affiliation, and the study is complemented by data on religious transmission. The results reveal that the period effect-largely influenced by sex abuse scandals within the Catholic Church-plays a significant role in decatholicization. Cohort effects also contribute, particularly among second- and third-generation post-Conciliar cohorts. Additionally, the research underscores the critical role of religious transmission in preserving religious affiliation across generations.