Yes / Objective: Previous research has shown that the degree to which individuals base their intentions on particular underlying cognitions (i.e., motives) significantly moderates the intention-behavior relationship. Studies have individually examined the moderating effect of intentions based on overall attitude, affective attitudes, injunctive norms, and moral norms. The present research used a within-persons approach to simultaneously test the moderating effects of intentions based on instrumental attitude, affective attitude, anticipated affective reactions, injunctive norms, descriptive norms, and moral norms on the intention-behavior relationship and the impact of controlling for intention stability, self-efficacy and past behavior. Main Outcome Measures: Self-reported performance of 20 health behaviors. Design: Adults (N = 366) completed questionnaires assessing instrumental attitude, affective attitude, anticipated affective reactions, injunctive norms, descriptive norms, moral norms, self-efficacy and past behavior at baseline; intentions at baseline and one month follow-up; and behavior at two month follow-up for 20 health behaviors. Results: When tested simultaneously using multi-level modelling the only significant moderator of the intention-behavior relationship was the extent to which intentions were based on anticipated affective reactions (intentions more strongly based on anticipated affective reactions were significantly stronger predictors of behavior). This effect remained when we also controlled for intention stability (which also moderated the intention-behavior relationship), self-efficacy and past behavior. Conclusions: Intentions based on anticipated affective reactions may be particularly important predictors of health behaviors. Studies manipulating such intentions to test their effects on behavior change are required. / The research reported here was supported by a grant from the British Academy