Background: Ovarian androgen production can be promoted by insulin resistance which leads to reproductive abnormalities in Polycystic Ovarian Syndrome (PCOS). A wide variety of female tissues can synthesize and secrete Prostate Specific Antigen (PSA). Androgens may take part a significant role in PSA secretion in PCOS. As insulin resistance stimulates androgen production, the baseline value of PSA may decline by insulin sensitising agents in PCOS. Present study is an attempt to measure the function of PSA as a marker of androgen excess in PCOS and to assess the role of insulin sensitising agent metformin in altering PSA level in PCOS.Methods: The study was undertaken to assess the insulin resistance, testosterone and PSA level in 45 women diagnosed as PCOS and 45 healthy controls. Alteration of insulin resistance, serum testosterone and PSA levels by metformin was also analysed.Results: A significant increase in testosterone, PSA level and insulin resistance was observed in PCOS cases when compared with control (p<0.001). When metformin was given for 4 months, improvement in insulin resistance and testosterone level was found in cases, but PSA values observed no change. Correlation was not found linking insulin resistance with PSA level prior to and after therapy.Conclusions: Serum PSA level could be detected in high significant concentration in PCOS women. Various researches explain that insulin resistance and BMI may perhaps control serum PSA level, but our result demonstrate no effect of insulin sensitising agent on serum PSA value.