Objective: Methods: To investigate the therapeutic benets of EMDR psychotherapy in treating MDD associated with PTSD. A pilot study was performed by using standardized EMDR psychotherapy in subjects with MDD associated with PTSD. The inclusion criteria were the followings; (1) Adults aged 18 years old or older, (2) Subjects being treated with antidepressants for at least two months assumably stable blood levels, (3) Subjects with depressive symptoms based upon the Patient Health Questionnaire (PHQ-9) depressive scale, (4) Subjects with positive score for traumatic events based upon the Children's Revised Impact of Events Scale-13 (CERIES-13, Thai version). The subjects were eligible if they fullled all four criterias. The subjects were treated with 60-90 minutes of EMDR psychotherapy twice a week for three weeks. The changes in PHQ-9 depressive scale, CERIES-13 scale, and Rosenberg self-esteem scale were obtained before the treatment, at the end of the treatment, and 3 months after treatment. The collective data was analyzed with a Paired t-test. Eighteen subjects with a mean age of 28 years were enrolled Results: in the study. The subjects had signicantly decreased PHQ-9 scale and CERIES-13 scale (mean difference [MD] = -11.47, p<0.001; MD = - 36.47, p<0.001, respectively), and had signicantly increased self-esteem scale (MD = 9.13, p<0.001) at 3 months after treatment when compared to prior results. The study demonstrated the therapeutic benets of adding EMDR psychothera Conclusion: py in MDD associated with PTSD patients who were currently treated with antidepressants. The benets of adding EMDR psychotherapy may possibly reduce depressive symptoms, PTSD symptoms and improve self-esteem in subjects. Further evaluation of the effectiveness of EMDR psychotherapy is in a guaranteed randomized controlled trial method