Recognition of the basal and postprandial components of hyperglycemia, in tandem with the development of new insulins and other clinical research, has led to a reassessment of type 2 diabetes mellitus treatment. In the future, insulin will be used earlier, treatment will intensify as the disease progresses, and combination therapy will be routine. Hyperglycemia can be controlled initially with sulfonylureas and metformin, agents that mainly improve control of fasting and preprandial glucose. When glycemic control can no longer be achieved with these and other oral agents alone, insulin treatment can be started as a single injection of a long-acting insulin. This method of supplementing basal insulin is safe, simple, and less likely to cause weight gain than multiple daily injections with shorter-acting insulins. Continuing oral agents during basal insulin therapy can provide a smoother transition to insulin and reduce the risk of loss of glycemic control. Of currently available insulins, glargine has the activity profile best suited to basal insulin therapy, with no prominent activity peak and a long duration of action, allowing a single daily injection in most cases. Although the traditional approach has been to introduce insulin therapy only after very high glucose values have persisted, despite prolonged use of oral agents alone, a more desirable strategy would be to prevent patients from ever experiencing the loss of glycemic control associated with hemoglobin A(1c) (HbA(1c)) elevations >7%. This goal could be achieved by diagnosing type 2 diabetes earlier in its course and by adding basal insulin to oral therapy much earlier. To maintain the recommended <7% HbA(1c) target level of control, treatments that target postprandial hyperglycemia will have to be added to basal insulin later on, as endogenous insulin continues to decline.