Objective : Since some studies have shown that the brain-derived neurotrophic factor(BDNF) has an important role in the pathophysiology of depression, this study investigated the relationship between BDNF genetic polymorphism and the long-term outcome of the antidepressant treatment. Method : One hundred and eight patients with major depressive disorder were evaluated for the long-term outcome(up to 3 years) of antidepressant treatment. The severity and improvement of depression were assessed with the Clinical Global Impression(CGI) Scale. The genotypes of BDNF 196A/G polymorphism in the patients were determined using Restriction Fragment Length Polymorphism(RFLP). Result : The genotypes of 128 patients were investigated and 95 patients of those have been evaluated for 3 years. No significant differences were noted comparing three-genotype groups for CGI scales at baseline, 4 weeks, 8 weeks, 1 year, 2 years and 3 years. Conclusion : This result shows that BDNF polymorphism investigated in this study was not associated with the long-term outcome of the antidepressant treatment. However, further studies with another BDNF polymorphism should be needed.