The present study examined whether exercise adherers and dropouts differ in their perceptions of success and, in turn, whether their social cognitions and behavior correspondingly differ. Using a prospective, observational design, exercise class participants were followed over 12 weeks of attendance. Social-cognitive measures were assessed at both early and late program while attendance was tracked for each half of the program. Multivariate analyses of variance (MANOVAs) using a 2 (Success/Failure) x 2 (Adherer/Dropout) factorial design revealed significant interactions for self-efficacy, affect, causal attributions, as well as rate of perceived exertion. Multiple main effects for perceived success and adherence were also found. The results suggest that "successful" dropouts possess social-cognitive characteristics that may enable them to resume their exercise participation at some later date. These findings provide evidence that the examination of perceived success allows for valuable insight into the differences among and between exercise adherers and dropouts, which may have implications regarding long-term exercise participation.