The present study sought to examine the role of social support and group cohesion in the compliance behavior of females required to exercise for health-related reasons. Compliance behavior was assessed as attendance and dropout behavior. Participants (N = 49) drawn from a clinical exercise group completed questionnaires to assess cohesion and social support. Discriminant function analyses were able to discriminate between high and low attenders as well as between dropouts and graduates. Participants reporting high scores on the support provision of reliable alliance and the cohesion factor of ATG-Task, along with low scores on the social support provision of guidance, were more likely to attend a higher proportion of classes. For dropouts, participants with higher scores on the support provision of reliable alliance were less likely to drop out. As a secondary objective, it was found that cohesion and social support variables both contributed to the successful prediction of attendance.