The most important question for clinicians caring for diabetic patients, and for the patient themselves, is whether the risk of complications can be altered by careful control of glycemia. Epidemiologic studies showed a strong relationship between glycemia and diabetic complications, in both type I and type II diabetes. There is a continuous relationship between prevailing glycemia and risk of progression of complications, implying that any improvement in glycemic control is beneficial. The debate of the question has ended--glucose control is important.