The objective of this research is to examine the factors that promote the onset and continuity of preventive health-care behaviors over the course of one's life. Using the life course paradigm as an overarching conceptual framework, hypotheses are developed that relate to the role of life events that trigger processes responsible for the initiation and discontinuation of three preventive health-care behaviors: exercising, using dietary supplements or vitamins, and having regular physical exams. The samples used are drawn from the United States, Thailand, South Korea, and Brazil. Results suggest that experience of life events and consequential life-course adaptation processes (socialization, stress and coping, and human development) are important predictors of initiation and discontinuation of preventive health-care behaviors. The relative influence of these explanatory variables varies across cultures, suggesting the importance of contextual factors in explaining preventive health-care behaviors. Implications for further research are also suggested.