Purpose: The purpose of this study was to test the effectiveness of a post-traumatic stress disorder management program in reducing firefighters’ post-traumatic stress and depression. Methods: This study employed a nonequivalent control group design using pretest and posttest measurements. Sampling was conducted with a convenient method. 44 firefighters (experimental group=22, control group=22) who were at high risk of post-traumatic stress disorder (PTSD) and depression were selected from 1,337 firefighters working in fire stations in multiple sites. Data were collected between August and October 2016. The post-traumatic stress disorder management program was provided to the experimental group for 8 weeks. Data were analyzed using descriptive statistics and chi-squared and independent t-tests. Results: Compared with the control group, participants in the experimental group showed significantly decreased scores for PTSD (t=-3.34, p=.002) and depression (t=-2.09, p=.043). Conclusion: Our study findings show that firefighters’ PTSD and depression can be systematically managed. Clinical practice should strengthen the ability to cope with PTSD by relieving the psychological trauma of firefighters who experience repeated traumatic events.