BACKGROUND: Conventional cardiovascular risk factors cannot fully explain high risk of cardiovascular disease in patients with non-insulin dependent diabetes mellitus(NIDDM). This study was undertaken to know whether plasma PAI-1 levels are increased in NIDDM patients, and to identify factors intluencing Pal-1 levels. METHODS: Forty three microalbuminuric, 41 normoalbuminuric NIDDM patients and 39 normal controls matched with age, sex and body mass index (BMI) participated in this study. Clinical characteristies and laboratory findings such as lipid profile, fasting serum C-peptide and PAI-1 levels were evaluated, RESULTS: NIDDM patients showed significantly higher PAI-1 levels than normal controls(44.3+17.4 ng/mL vs. 26.3+12.6ng/mL, p<0.05). However, we failed to show the differences in PAI-1 levels between NIDDM patients with microalbuminuria and normoalbuminuria. PAI-1 levels were significantly correlated to BMI, fasting plasma glucose, HbA1, triglyceride and serum C-peptide levels. Multiple regression analysis showed that serum triglyceride and fasting serum C-peptied levels were independently related to PAI-1 levels. Conclusion; These findings suggested that elevated PAI-1 levels may contribute to increased risk of cardiovascular disease in patients with NIDDM.