Aim of the Study: An impaired flow mediated vasodilation (FAD) is regarded as an early functional, the intima media thickness (IMT) as an early morphological marker of atherosclerosis. Changes of both parameters are described in diabetic patients. The role of the coagulation and fibrinolysis system in these early stages of atherosclerosis is not clear.Methods: Using high resolution ultrasound we measured both FAD (brachial artery) and IMT (common carotid artery) in 17 long-term well controlled, nonalbuminuric IDDM- and 25 NIDDM subjects and healthy controls matched for number, age, gender and lumen diameter of the A. brachialis. The parameters for coagulation (thrombin-antithrombin III complex (TAT)) and fibrinolysis (tissue-plasminogen activator (TPA), plasmin-a 2 -antiplasmin complex (PAP)) were determined by ELISA. Statistical analysis was performed by T-Test, ANCOVA with BMI, IMT, and HbA1c as possible confounders for FAD or IMT and linear regression were calculated between FAD or IMT and PAP, p < 0.05 was considered as significant, numbers are given as means ± SD.Results: In both IDDM (1214 ± 644 vs 847 ± 491 μg/l, p < 0.05) and NIDDM patients (1125 ± 589 vs 847 ± 449 μg/l, p < 0.05) PAP is increased, while TAT and TPA do not differ from the controls. In NIDDM patients FAD is impaired (3.8 ± 3.3 vs 6.9 ± 4.4%, p < 0.01) and IMT is increased (0.72 ± 0.14 vs 0.62 ± 0.10 mm, p < 0.01), but not in this selective group of IDDM patients. There is no correlation between FAD or IMT and PAP in NIDDM patients.Conclusion: In diabetic patients TAT and TPA do not differ from healthy controls, PAP is elevated in both IDDM and NIDDM patients. But these increased levels of PAP are not associated with early stages of atherosclerosis - as judged by FAD and IMT - in diabetic patients.