Objective: The aim of this study is to investigate whether cognitive behavioral therapy intervention lead to improvement in psychological parameters and obesity parameters. Methods: Ten participants, nine females and one male, were assigned to two different cognitive behavioral therapy (CBT)-based groups. The adolescents' mean age was 14.10 +/- 1.79 years and their mean body mass index was 29.95 +/- 4.18 kg/m(2). The CBT comprised of nine sessions followed by one parent session. The participants also received lifestyle interventions which include weekly weight checks, diet, and exercise. Results: The evaluations of the nine CBT sessions showed a signifi-cant reduction in depressive symptoms, social anxiety, social phobia, and a significant improvement in self-es-teem, but the BMI scores remained unchanged which was a deviation from our expectation. Discussion: This is the first study in Turkey to evaluate the impact of group-based CBT on depressed adolescents. The results demonstrate that further researches are needed, with the objective of developing cognitive-behavioral interven-tions that help patients to lose weight and maintain their weight at a healthy level.