The importance of diabetes mellitus (diabetes) as a cause of mortality and morbidity is well known. The number of patients increases alongside aging of the population and increase in the prevalence of obesity and sedentary life style. Diabetes affects approximately 8% of the USA population. Type I (insulin-dependent) diabetes occurs in 20% of cases, and type II (insulin-independent or maturity onset) diabetes occurs in 80% of the diabetic population diabetes mellitus type II is preceded by longstanding asymptomatic hyperglycemia, which accounts for the development of long-term diabetic complications. The main macrovascular complications for which diabetes has been a well established risk factor throughout the cardiovascular system, are: coronary artery disease (CAD), peripheral vascular disease (PVD), increased intima-media thickness (IMT) and stroke. Considering the cardiovascular surgeon, diabetes is associated with an increased rate of early and late complications following coronary artery bypass grafting. Diabetic patients have also been known to have an increased incidence of complications after elective major vascular surgery such as carotid endarterectomy (CEA) and leg amputations due to PVD. Cardiovascular surgeons frequently treat diabetic patients either because diabetes is incidental to another disease requiring surgery, or due to diabetes-related complication such as occlusive vascular disease, neuropathy or infection. Approximately 50% of diabetics undergo one,or more operations during their lifetime. This paper reviews the relationship between diabetic patients and their cardiovascular surgeons. In order to understand this relationship, one must first examine the underlying mechanisms by which hyperglycemia causes hazardous pre and post operative consequences. Then, one must examine the existing evidence of how diabetes correlates with these cardiovascular consequences, followed by the need for multidisciplinary team work which helps the surgeon to cope with diabetic patients.