Objective To evaluate the therapeutic effects of metformin hydrochloride and rosiglitazone maleate tablets on insulin resistance and androgen concentration in obese and nonobese women with polycystic ovarian syndrome (PCOS).Methods Seventy women with PCOS were enrolled into this study according to the diagnostic criteria of Rotterdam conference (2003).The women with PCOS were divided into the over weight/obese group (body mass index ≥ 25 kg/m2,n =34) and the nonobese group (body mass index＜25 kg/m2,n =36).All women with PCOS took metformin hydrochloride and rosiglitazone maleate tablets twice daily for 3 months.The following indexes were measured before and after the treatment:height,weight,waist circumference,hip circumference,fasting plasma glucose,fasting plasma insulin,luteinizing hormone (LH),follicle stimulating hormone (FSH),total testosterone,free testosterone,follicular number and ovarian area,body mass index,waist to hip ratio,and homeostasis model assessment for insulin resistance (HOMA-IR) were calculated.Results (1) Compared with the nonobese group,dramatic increases in HOMA-IR and follicle number were observed in over weight/obese group(P＜0.05),while LH,LH/FSH,total testosterone,free testosterone showed no significant difference between two groups.(2) After the treatment with metformin hydrochloride and rosiglitazone maleate tablets,weight,body mass index,fasting plasma glucose,fasting plasma insulin,HOMA-IR significantly decreased in two groups (P ＜ 0.05).There were also significant declines of LH,LH/FSH,free testosterone,ovarian area,follicular number,especially in the over weight/ obese women with PCOS (P＜0.05),while total testosterone and FSH did not change significantly.(3) The incidence of gastrointestinal adverse reactions in nonobese and over weight/obese group was 9.3％ and 6.3％ respectively,and no liver toxicity,edema,hypoglycemia and other adverse reactions was observed during treatment.Conclusion Compared with the nonobese group,there were severer insulin resistance and more marked polycystic change of ovary in over weight/obese women with PCOS,while total testosterone and free testosterone showed no significant difference between two gruops.Metformin hydrochloride and rosiglitazone maleate tablets can ameliorate insulin resistance and polycystic ovary,and also reduce body mass index and free testosterone in women with PCOS particularly in the over weight/obese individuals.