This project seeks to advance our understanding of how religious and scientific meaning systems conjointly influence individuals’ understanding of the world and their adaptive behavior based on this understanding. Five sequential studies are proposed: In Study 1, we will establish the most useful way to assess individual differences in the relative influence of religion and science on meaning systems. Study 2 aims to identify social and psychological determinants of this relative influence. In Study 3, the impact of the relative influence of religion and science on individuals’ general understanding of the world and their adaptive behavior (mental and physical health, health behaviors) is assessed. Study 4 examines relative influence of religious and scientific meaning systems on cancer survivors’ understanding of and coping with their cancer, including attributions for cause and cure, treatment decision making and adherence, and health behavior change. Study 5 takes a within-person approach to identify situational predictors of when religious versus scientific meaning systems come to the fore. Collectively, these studies will advance our understanding of the conjoint influences of religion and meaning in our lives and lay the foundation for future research.