Objective Written exposure therapy (WET) is exposure therapy for post-traumatic stress disorder (PTSD). Compared to evidencebased treatments for PTSD, WET requires only five sessions, has a shorter session time, and no between-session assignments. The current study examined the efficacy of WET among Korean patients with PTSD due to various traumatic events on PTSD symptoms, depressive symptoms, and global functioning levels. Methods The study recruited 41 patients with a current primary diagnosis of PTSD in psychiatric outpatient clinics. Assessments were conducted at baseline, and at 6, 12, and 24 weeks following the first treatment session. Results In total, 25 patients started WET. Findings showed a significant reduction in the rate of PTSD diagnosis and symptom severity scores. Fourteen of 23 (60.9%) patients at 6 weeks, 15 of 22 (68.2%) patients at 12 weeks, and 14 of 18 (77.8%) patients at 24 weeks no longer met the diagnosis of PTSD. Depressive symptoms and global function scores also improved after WET. The dropout rate was 8% (n=2). Conclusion This study suggests the feasibility of implementing WET among various types of patients with PTSD in Korea and other Asian countries.