In this study, we examined the effects of sweat therapy on group dynamics and affect. Sweat therapy is the combination of intense heat exposure with psychotherapy or counseling (Colmant & Merta, 1999; 2000). Twenty-four undergraduates were separated by sex and randomly assigned to eight sessions of either a sweat or non-sweat group counseling condition. Measures included the Critical Incidents Questionnaire, the Harvard Community Health Plan Group Cohesiveness Scale, and the Positive and Negative Affect Scale. The sweat therapy participants reported more therapeutic factors having an impact on their group counseling experience, rated sessions as more beneficial, and interacted with stronger group cohesion than non-sweat therapy participants. There were no significant group differences in affect on immediate post-session measures. Implications for future research are discussed.