Cardiovascular disease is a frequent complication of insulin-dependent diabetes mellitus (IDDM), but the prevalence, interrelations, and risk factors of its principal components (coronary, cerebrovascular, and lower-extremity arterial disease) and of medial arterial wall calcification are not well understood. To address these issues, data from the Epidemiology of Diabetes Complications Study (n = 657) baseline examination were examined. The term coronary heart disease (CHD) was applied to those with myocardial infarction or angina, whereas lower-extremity arterial disease (LEAD) was applied to those who had undergone amputation of a lower limb or who had an ankle to arm blood pressure ratio less than 0.8 at rest or after exercise. Calcification of the lower-extremity arteries was considered to be present if ankle pressure was more than 100 mm Hg higher than brachial pressure. Although the prevalence of CHD was low, LEAD was significantly more common in women than in men (p less than 0.01), whereas calcification was more frequent in men than in women (p less than 0.01). Ten percent of those with LEAD also had CHD, and 8% with LEAD had calcification. Modeling of potential risk factors (e.g., diabetes duration and glycosylated hemoglobin) revealed that duration, female gender, fibrinogen, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and high density lipoprotein cholesterol to apolipoprotein A-I ratio were independent predictors of LEAD, whereas for CHD only, diabetes duration and hypertension contributed to CHD. Calcification revealed a mixed pattern, with duration, hypertension, and triglyceride to apolipoprotein A-I ratio being the statistically significant associated factors. The results suggest that although LEAD, CHD, and calcification often coexist, their risk factor profiles differ.