Methods: In this study, we investigated the association with rs6265 (BDNF), and rs11030101 (BDNF), rs3813034 (Serotonin Transporter, SLC6A4) rs4680 (TPH1), rs1800532 (TPH1), rs1386493 (TPH2), rs6311 (HTR2A), rs6313 (HTR2A), rs6314 (HTR2A), rs6296 (HTR1B), gene polymorphism in Korean suicides with major depressive disorder who visited the emergency room. Here, SLC6A4 is linked to major depressive disorder.