Objectives : The purpose of current study was comparison of transdiagnostic group therapy with classic group cognitive therapy on positive and negative affects and emotion regulation. Method: Thirty-three college students with anxiety and depressive symptoms were randomly assigned to two groups and participated in eight two-hour sessions. Results: In both groups, the treatment method was effective on emotion regulation components and positive and negative affects after interventions. Analysis of covariance showed the higher effectiveness of transdiagnostic on improvement of reappraisal (p=0.01) and increase of positive affection (p=0.001). Conclusion: The effectiveness of transdiagnostic group therapy in improving emotion regulation and positive affects was higher than classic group cognitive therapy. Clinical implications of findings are discussed.