Most patients with type 2 diabetes mellitus develop cardiovascular disease (CVD), with substantial loss of life expectancy. Nonfatal CVD contributes greatly to excess healthcare costs and decreased quality of life in patients with diabetes. The current epidemic of obesity has raised expectations that CVD associated with type 2 diabetes will become an even greater public health challenge. Despite the importance of this health problem, there is a lack of definitive data on the effects of the intensive control of glycemia and other CVD risk factors on CVD event rates in patients with type 2 diabetes. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial is a randomized, multicenter, double 2 - 2 factorial design study involving 10,251 middle-aged and older participants with type 2 diabetes who are at high risk for CVD events because of existing CVD or additional risk factors. ACCORD is testing the effects of 3 medical treatment strategies to reduce CVD morbidity and mortality. All participants are in the glycemia trial, which is testing the hypothesis that a therapeutic strategy that targets a glycosylated hemoglobin (HbA1c) level of <6.0% will reduce the rate of CVD events more than a strategy that targets an HbA1c level of 7.0%-7.9%. The lipid trial includes 5,518 of the participants, who receive either fenofibrate or placebo in a double-masked fashion to test the hypothesis of whether, in the context of good glycemic control, a therapeutic strategy that uses a fibrate to increase high-density lipoprotein cholesterol and lower triglyceride levels together with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) to lower low-density lipoprotein cholesterol will reduce the rate of CVD events compared with a strategy that uses a statin plus a placebo. The blood pressure trial includes the remaining 4,733 participants and tests the hypothesis that a therapeutic strategy that targets a systolic blood pressure of <120 mm Hg in the context of good glycemic control will reduce the rate of CVD events compared with a strategy that targets a systolic blood pressure of <140 mm Hg. The primary outcome measure for all 3 research questions is the first occurrence of a major CVD event, specifically nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. Upon the expected completion of participant follow-up in 2009, the ACCORD trial should document for the first time the benefits and risks of intensive glucose control, intensive blood pressure control, and the combination of fibrate and statin drugs in managing blood lipids in high-risk patients with type 2 diabetes.