METHODS: A total of 148 depressive patients receiving escitalopram 10-20 mg/day were genotyped for 5HTTLPR and rs25531 polymorphisms. Clinical assessment was done at baseline and after 4, 8, and 12 weeks using the 17-item Hamilton Depression Rating Scale (HDRS-17), Montgomery-Asberg Depression Rating Scale (MADRS), and Clinical Global Impression Scale (CGI). At the end of week 12, patients were defined as responders and non-responders based on HDRS17 and MADRS scores. Chi-square test and logistic regression analysis were performed to investigate the genotypic influence on treatment response. Comparison of continuous variables among different groups was done using Student's t test or one-way ANOVA.