We investigated the usefulness of the fluorogenic prothrombin time (FPT) for detection of hypercoagulability and its association with hyperlipidemia in 19 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 10 healthy control subjects, compared with plasma levels of fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and D-dimer. We also evaluated the effect of bezafibrate on hypercoagulability in 10 hyperlipidemic NIDDM patients. The plasma levels of FPT and fibrinogen were significantly higher in hyperlipidemic NIDDM patients than in normolipidemic NIDDM patients and controls. Plasma levels of PAI-1 and D-dimer were significantly higher in normolipidemic and hyperlipidemic NIDDM patients compared with controls. The FPT was correlated with the HbA1c, the body mass index, and levels of total cholesterol, fibrinogen and PAI-1. Six-months therapy with bezafibrate reduced the levels of FPT, triglycerides and basal insulin, but did not alter levels of fibrinogen, PAI-1 and D-dimer. Our results showed that the FPT was useful for detection of hypercoagulability and evaluation of the effect of drugs. The increased FPT in patients with NIDDM suggested that hypercoagulability was present in association with hyperlipidemia.