Worry and risk perceptions are generally found to be independently associated with health-promoting behaviors, although it is unknown whether they interact in ways that potentially dampen the effect of either construct on behavior. In this hypothesis-generating study, cancer-related worry and risk perception, and their interaction, were used to predict odds of meeting 5-a-day fruit and vegetable consumption guidelines and engaging in any exercise using data from a nationally representative sample (N = 10,230). Risk perception was not associated with either behavior; worry was associated only with exercise (OR = 1.77, 95% CI: 1.16, 2.70, p < .01). More important, their interaction was associated with these behaviors in a counterintuitive manner; among those higher in worry, higher levels of risk perception were associated with lower vegetable consumption (OR = 0.79, 95% CI: 0.62, 1.00, p < .05) and exercise (OR = 0.77, 95% CI: 0.63, 0.95, p = .01). These results suggest the hypothesis that, among people high in worry, attempts to increase risk perception could be counterproductive. These and related findings suggest the importance of distinguishing worry from risk perception, and future research is necessary to determine the causal nature of these associations.