OBJECTIVE: This study was performed to evaluate the effect of isoflavone supplementation on hormone levels, lipid profiles and total antioxidant status in patients with polycystic ovary syndrome. METHODS: Total 11 women with polycystic ovary syndrome were supplemented daily with 150mg of isoflavone for 6 months. Blood samples were collected 0, 3, and 6 months after supplement of isoflavone for analysis of LH, FSH, E2, testosterone, free testosterone, SHBG levels, serum lipid profiles, and total antioxidant status (TAS). RESULTS: After 6 months isoflavone supplementation, the hormone levels did not change significantly. Serum lipid profiles did not show any significant change in total cholesterol, LDL-cholesterol, triglyceride, lipoprotein(a), and free fatty acid levels. However, there was significant increase in HDLcholesterol (p<0.05) for 3 months. Total antioxidant status was increased significantly after isoflavone supplementation for 6 months (p<0.05). CONCLUSION: Isoflavone supplementation showed positive effects on the HDL-cholesterol and total antioxidant status. it is implicated that isoflavone supplementation will may have a effect on cardiovascular disease in patients with polycystic ovary syndrome.