The purpose of the study was to evaluate the plasminogen activator inhibitor-1 (PAI-1) levels and PAI-1 activity in young and lean women with PCOS and to compare with controls matched for age and weight. Thirty two women with PCOS and 25 weight and age-matched healthy controls participated in this study. Patients were evaluated clinically and by pelvic ultrasound and fasting blood samples were taken for hematological and biochemical tests. Fasting insulin, glucose, lipid profile, FSH, LH, PRL, testosterone, SHBG, 17-hydroxyprogesterone, androstenedione, PAI-1 antigen; PAI-1 activity, insulin sensitivity indices (HOMA and QUICKI) were measured. PAI-1 Ag and activity were significantly higher in PCOS women than healthy control group. PAI-1 levels were directly correlated with BMI, insulin levels and insulin sensitivity indices. PAI-1 activity was also correlated with insulin levels and insulin resistance. As a conclusion PAI-1 Ag levels and activity were increased in lean PCOS women and these were directly correlated with insulin resistance. The finding may contribute to evidence of increase risk of cardiovascular disease and anovulatory infertility in PCOS women.