Cardiovascular disease is a major causes of morbidity and mortality in patients with non-insulin-dependent diabetes mellitus (NIDDM). With an increase in the number of older diabetic persons, an increase in U.S. minority populations with high rates of diabetes, and the proven success of new methods to reduce microvascular complications, the importance of diabetic macrovascular complications will increase. The relative effectiveness of different treatments to reduce the incidence of diabetic cardiovascular complications is poorly understood. In addition to relative efficacy, issues related to patient burden and the economic cost of different treatments must be considered. Some of the information needed to improve therapy therapy will be available soon from ongoing clinical trials. Obtaining definitive answers to other questions, especially those related to the relative benefit of intensive glucose level control compared with control of other known cardiovascular disease risk factors, will require additional studies. Although several questions unique to diabetic patients remain unanswered, results of previous clinical trials done among largely nondiabetic participants can be used to develop interim recommendations for cardiovascular disease prevention. Until definitive guidelines for prevention are established, combining aggressive therapy for known cardiovascular disease risk factors with efforts to normalize the glucose level offers the best chance to reduce the higher risk for cardiovascular disease associated with NIDDM.