Elevated PAI-1 levels were described in different insulin resistant conditions, incl. diabetes mellitus type II. In its formation probably several stimulating factors participate. Hitherto accomplished studies suggest not only the important effect of insulin acting synergically with very low density. lipoproteins (VLDL) on hepatocytes but also the importance of the endothelial pool where the action of proinsulin, VLDL and cytokines in synergy with Cai-dependent stimuli (oxidation stress, thrombin) is involved. Under certain circumstances also another adipocyte compartment may play a role, and a significant role of thrombocytes in raising the PAI-1 level cannot be ruled out either. A more detailed analysis of the raised PAI-1 level in different patients could extend the possibilities of therapeutic reduction of levels of this important risk factor of atherosclerosis.