Type 2 diabetes mellitus is a prevalent disorder diagnosed by the presence of hyperglycemia, although insulin resistance frequently precedes the onset of hyperglycemia. Metabolic abnormalities, such as dyslipidemia, increased markers of atherosclerotic and inflammatory states, and increased free fatty acid flux, also precede the detection of hyperglycemia in many patients. Not surprisingly, clinical morbidities from complications of type 2 diabetes often are present at the time of diagnosis; these complications include both microvascular and macrovascular disease. The macrovascular complications of type 2 diabetes are associated with a variety of risk factors for cardiovascular disease. Insulin resistance appears to be the risk factor that best correlates with metabolic abnormalities prior to diagnosis and is fundamentally linked to development of cardiovascular disease in patients with type 2 diabetes. This article will review the unifying finding of insulin resistance in type 2 diabetes with both metabolic and cardiovascular consequences.