This report summarizes the current state of knowledge concerning the cardiovascular system in various animal models of diabetes and presents their major strengths and weaknesses for studying the important research questions in the field. Nonhuman primates have many desirable features for studies on the macrovascular and cardiac complications of the disease as well as risk factor alterations, but their availability, cost, and maintenance present practical disadvantages. The spontaneous rodent models of diabetes currently are not considered very useful for cardiovascular research, but they have not been well characterized with respect to most aspects of their cardiovascular system. Alloxan-diabetic rabbits offer some promise for examining the effects of diabetes on atherogenesis, lipoprotein metabolism, and cardiomyopathy, but additional research is required to validate their usefulness. Insufficient data are available on canine and swine models of diabetes to judge their merits for cardiovascular research. The Task Force recommends: (1) additional longterm investigations to determine the extent and severity of cardiovascular complications in the well-characterized rodent models and in diabetic rodents with multiple risk factor abnormalities; (2) further studies on the macrovascular disease and lipoprotein abnormalities of the alloxan-diabetic rabbit and the development of rabbit colonies with spontaneous diabetes; (3) increased emphasis on such potentially important but neglected areas of research in diabetic animals as the intramyocardial circulation, adventitial blood vessels, blood pressure, platelet function, blood coagulation, blood rheology, and autonomic nervous function; (4) long-term studies on the influence of control of hyperglycemia and of insulin therapy on cardiovascular complications in diabetic animals; and (5) encouragement of use of diabetic nonhuman primates for cardiovascular research and institution of measures to increase their supply and availability by expanding current colonies, screening newly imported animals for diabetes, and establishing a visiting scientist's program allowing investigators to study diabetic primates at resource centers.