The ACE gene has recently been shown to be associated with myocardial infarction, especially in subjects considered at low risk for coronary heart disease (CHD) according to common classification criteria. The possible relationship between deletion polymorphism in this gene and CHD risk factors, as well as asymptomatic extracoronary atherosclerosis, has been investigated in the present study. One hundred and seventy-four subjects, enrolled in a cardiovascular disease prevention study, underwent clinical and biochemical examination and ACE-I/D polymorphism determination. Subjects > 45 years of age (n = 107) also received echo-Doppler examination of the carotid arteries. Based on the results of ACE-I/D polymorphism, subjects were divided into three groups: homozygous for deletion (D/D), homozygous for insertion (I/I) and heterozygous (I/D). The prevalence of CHD risk factors as well as of extracoronary atherosclerosis was similar in the three genotype groups. Similarly, there was no association between the presence of atherosclerotic lesions and genotype in subjects at low and high CHD risk. Ten subjects with diabetes mellitus had ACE-D/D genotype. Among these subjects seven had hypertension. Eight subjects with diabetes mellitus had ACE-I/D genotype and only one of these was hypertensive. None of the ACE-I/I subjects was diabetic. ACE-I/D polymorphism seems to play a role in the development of hypertension, at least in diabetic subjects. Its determination may help to identify and monitor diabetic subjects prone to hypertension.