The purpose of this study was to determine the effectiveness of teaching mindfulness-based stress reduction in reducing psychological symptoms in male adolescents living in the dorms. This study is a quasi-experimental clinical research (pre-test, post-test with a control group). In March 1391, 30 individuals were randomly selected from Heday at night schools (in Saghez) and 30 others were selected from Marefat night school. Randomly one of these groups was selected as the experimental group (30 persons from Marefat School) and the other group was selected as the control group (30 persons from Heday at School). The experimental group took the MBSR (mindfulness-Based Stress Reduction) Guide for eight sessions. SCL-90 questionnaires were performed on all subjects before and after the intervention. To analyze the data, we used the covariance analyses. The results indicated that MBSR is effective in reducing psychological symptoms of anxiety, depression, Intellectual and practical obsession, somatic symptoms and hostility.