Thrombophilia with a contemporary reduction of fibrinolytic activity has been observed both in diabetes mellitus and hypertension. Previously, we found a relationship between plasminogen activator inhibitor Type 1 (PAI-1) and lipoprotein(a) [Lp(a)] in Type 2 diabetes mellitus patients without complications. We hypothesised that this relationship could be due to a compensatory mechanism able to lower the risk of hypofibrinolysis as found in Type 2 diabetes mellitus. The present work was aimed at investigating the influence of concurrent hypertension and diabetes mellitus on the plasma levels of these two fibrinolytic inhibitors. In addition, other risk factors, known to influence the fibrinolytic parameters, were taken into account. Forty-nine Type 2 nonhypertensive diabetic patients without complications, 47 Type 2 hypertensive diabetic patients without complications, 54 non-diabetic hypertensive subjects without complications as well as 87 control subjects were studied. Plasma concentrations of Lp(a), PAI-1 antigen and activity, and the main parameters of oxidative, lipo- and glycometabolic balance were determined. Significant statistical differences between diabetic and non-diabetic subjects were found concerning triglycerides and antioxidant defence (p<0.01). Analysis of variance showed the F test statistically significant in evaluating the Log PAI-1/Lp(a) (p = 0.02). Correlation analysis between Log PAI-1 antigen and Lp(a) was significant in non-hypertensive diabetic patients, as expected (r = -0.38, p<0.01), and even stronger in hypertensive diabetic patients (r = -O.72,p<0.01). These results allow to hypothesise that the relationship between PAI-1/Lp(a) could be determinant in avoiding vascular complications due to diabetes mellitus and hypertension.