Background: This study was designed to investigate the effect of metformin and flutamide alone or in combination with anthropometric indices and laboratory tests of obese/overweight PCOS women under hypocaloric diet. Methods: This single blind clinical trial was performed on 120 PCOS women. At the beginning, hypocaloric diet was recommended for the patients. After one month while they were on the diet, the patients were randomly divided in 4 groups; metformin (500 mg, 3/day), flutamide (250 mg, 2/day), combined, metformin (500 mg, 3/day) with flutamide (250 mg, 2/day) and finally placebo group. The patients were treated for 6 months. Anthropometric indices and laboratory tests (fasting and glucose-stimulated insulin levels, lipid profile and androgens) were measured. A one-way ANOVA (Post Hoc) and paired t-test were performed to analyze data. A p≤0.05 was considered statistically significant. Results: After treatment, reduction in weight, BMI, hip circumference was significantly greater in the metformin group in comparison to other groups (p<0.05). In addition, the fasting insulin was significantly greater in metformin group and flutamide group in comparison to metformin+flutamide and placebo groups after treatment (p<0.05). Within groups, insulin level showed significant changes (before and after treatment) in metformin+flutamide group and LDL reduction was significant in flutamide group before and after treatment. Post hoc tukey and two-tailed with p≤0.05 were used to define statistical significance. Conclusion: Using combination of metformin and flutamide improves anthropometric indices and laboratory tests in obese/overweight PCOS women under hypocaloric diet.