Objective To evaluate the impacts of rosiglitazone and metformin on ovarian response, hirsutism and insulin action in women with polycystic ovary syndrome (PCOS). Methods Ninety women resistant to clomiphene citrate with PCOS were randomized, 40 cases to rosiglitazone group, 50 cases to meformin group. Rosiglitazone and metformon were administered for 6 months in combination with clomiphene citrate on cycle day 5 th to 9 th, respectively. The clinical evaluations were performed monthly. Reproductive hormone, serum glucose and insulin levels were observed before and after treatment. The data were analyzed using repeated analysis of variance (ANOVA). Results There were significant changes in reducing hirsutism score, serum testosterone level, LH/FSH ratio, and restoration of ovarian ovulation after metformin or rosiglitazone administration respectively (P<0.05). Insulin sensitivity was more significantly improved in the rosiglitazone group than in metformin group (P<0.05) After treatment. Homa IR and Homa β were decreased from 1.54±0.34 to 0.83±0.38 and from 5.83±0.55 to 4.95±0.54 (P<0.05) in the rosiglitazone group. The body mass index(BMI) was decreased from 25.30±3.64 to 23.83±2.32 in the metformon group (P<0.05). There were no significant changes in ovulation rate and pregnancy rate between groups (P>0.05). Conclusion Rosiglitazone can increase insulin sensitivity. Metformon may reduce BMI. They all restore regular menstrual cycles, increase pregnancy rate, and reduce testosterone and LH concentration in women with polycystic ovary syndrome. Objective To evaluate the impacts of rosiglitazone and metformin on ovarian response, hirsutism and insulin action in women with polycystic ovary syndrome (PCOS). Methods Ninety women resistant to clomiphene citrate with PCOS were randomized, 40 cases to rosiglitazone group, 50 cases to meformin group Rosiglitazone and metformon were administered for 6 months in combination with clomiphene citrate on cycle day 5 th to 9 th, respectively. The clinical evaluations were performed on monthly. Reproductive hormone, serum glucose and insulin levels were observed before and after treatment. Results using repeated analysis of variance (ANOVA). Results There were significant changes in reducing hirsutism score, serum testosterone level, LH / FSH ratio, and restoration of ovarian ovulation after metformin or rosiglitazone administration (P <0.05). significantly improved in the rosiglitazone group than in metformin group (P <0.05) After treatment . The Homa IR and Homa β were decreased from 1.54 ± 0.34 to 0.83 ± 0.38 and from 5.83 ± 0.55 to 4.95 ± 0.54 (P <0.05) in the rosiglitazone group. The body mass index (BMI) was decreased from 25.30 ± 3.64 to 23.83 There was no significant changes in ovulation rate and pregnancy rate between groups (P> 0.05). Conclusion All Rosiglitazone can reduce insulin sensitivity. They all restore regular menstrual cycles, increase pregnancy rate, and reduce testosterone and LH concentration in women with polycystic ovary syndrome.