The increased risk of developing cardiovascular disease in diabetic population has been well documented, but the prevalent mechanism of this susceptibility is still only partly explained. We compared the impact of diabetes on ischemic heart disease in patients hospitalized in a public general hospital over a 10-year period. The prevalence of coronary heart disease (CHD) was consistently higher among diabetic population [namely, among non-insulin-dependent diabetes mellitus (NIDDM) patients] when compared with the nondiabetic population. The prevalence was similar in both genders, increasing with age, and was independent from body-mass index, history of smoking, metabolic control, or lipid pattern. Heart rate and blood pressure levels were significantly higher in NIDDM patients with CHD; similarly, there was a significant association between ischemic heart disease and atherosclerotic peripheral artery disease prevalence, and this trend was observed even in subjects with impaired glucose tolerance. These observations support the evidence that diabetes exerts a deleterious effect on general risk factors of atherosclerosis and increases susceptibility to cardiovascular disease by itself as an "independent" risk factor; on the other hand, the epidemiological evidence of an excessive occurrence of type II diabetes in individuals with pre-existing vascular disease suggests a genetically determined link between metabolic disturbances and cardiovascular disease.