Background: Maintaining physical health and psychological readiness in military personnel and soldiers is very important. Objectives: This study aimed to investigate the effects of social group work based on cognitive-behavioral therapy approach on the soldiers' level of depression. Methods: This is an experimental study conducted in 2016 -2017. 60 soldiers of a military setting with mild to severe depression were randomly selected. Then, the soldiers were randomly assigned to intervention and control groups. Soldiers in the intervention group participated in cognitive-behavioral group therapy sessions that were conducted by a master of social worker who was trained. The level of depression was assessed before and after intervention with Beck depression inventory. Data were analyzed with statistical software SPSS (version: 16) at the level of P < 0.05.