Atherosclerosis is more extensive and occurs earlier in diabetics compared with the general population. The pathophysiology of atherosclerosis is not fully established. We compared the activity of two blood clotting agents, activated factor VII (VIIa) and von Willebrand factor (vWF), in diabetic and non-diabetic subjects with coronary artery disease. According to clinical features, subjects were placed in one of four groups: Group I, non-insulin-dependent diabetes mellitus (NIDDM) with coronary heart disease (CAD) (n = 16); Group II, NIDDM (n = 15); Group III, CAD with no presence of diabetes (n = 17); and Group IV, healthy volunteers (n 15). The level of factor VIIa was higher in Group I compared with all other groups, and was significantly higher in Group II compared with Group III and Group IV. Activity of vWF was higher in Group I compared with Group II, Group III and Group IV. There was no statistical difference between Group II and Group III. There was no significant correlation between concentration of blood glucose, total cholesterol or triglyceride, duration of diabetes and either factor VIIa or vWF activity. The results of this study suggest that increased activity of plasma vWF and factor VIIa may be useful markers to identify ischaemic heart disease risk in NIDDM subjects.