PAI-1 antigen, tPA antigen and thrombin - antithrombin III complexes (TAT) levels were measured in 10 males with stable angina and type-II diabetes mellitus and in 16 males with stable angina without diabetes or other risk factors (hyperfibrinogenaemia, hyperlipidaemia, diabetes, hypertension, smoking and obesity) known to increase PAI levels. Ten healthy men of equivalent age served as controls. Because only diabetics with coronary artery disease (CAD) showed a decreased fibrinolytic capacity, a second study was performed on the 16 non-diabetic CAD patients to determine whether submaximal workload induces significant changes of tPA and PAI levels. TAT levels were increased in CAD, and significantly so in the diabetic group. tPA levels were increased only in the CAD patients without diabetes. PAI levels were significantly increased in diabetic CAD patients (5.26 +/- 1.96 ng/ml) but not in the stable angina patients without diabetes (2.97 +/- 1.44 ng/ml). Immunologically-reactive tPA released after exercise was higher in the 16 CAD patients without diabetes than in controls. Our data could indicate that in stable angina without diabetes there is no chronic latent activation of the clotting system, with no impairment of fibrinolytic activity. On the other hand, the presence of diabetes mellitus seems to influence the fibrinolytic capacity in CAD, particularly increasing PAI levels.