The present set of studies examined whether social support strengthens the relationship between worry and health decision-making about prevention of skin and colorectal cancer in high risk individuals. Two cross-sectional (Studies 1a and 1b) and two longitudinal (Studies 2 and 3) designs were used to test the hypothesis that higher levels of social support would strengthen the positive relationship between worry and adaptive health decision-making. Although support for this hypothesis was not found, main effects of social support and worry were found in some of the studies. Structural and functional social support predicted intentions to use sunscreen in Study 1a, a nationally representative study. However, worry predicted reported use of sunscreen and intentions to use sunscreen at baseline and 30-day follow-up in Study 3, a longitudinal study. In regard to health decision-making about colorectal cancer prevention, Study 1b, a nationally representative study, revealed elevated levels of structural support in those who had been screened for colorectal cancer. Study 2 revealed a trend towards significance for the moderating role of social support in the relationship between worry and intentions to be screened for colorectal cancer at follow-up; however, it was not in the predicted direction. Theoretical and clinical implications of the findings are identified as well as directions for future research.