Continuous subcutaneous insulin infusion (CSII) therapy using external infusion pumps provides an alternative to multiple daily injections (MDI) for insulin-dependent diabetics who require intensive insulin therapy. CSII allows for the delivery of regular insulin continuously at preset basal rates and at bolus doses, which can be varied in response to insulin needs of the patient. Intensive insulin therapy by CSII or MDI was administered to diabetics to improve control of their blood glucose levels and to assess its effects on the development of complications such as retinopathy and nephropathy. CSII appeared to be as effective as MDI in attaining near-normoglycemia and improving metabolic control in patients with insulin-dependent diabetes mellitus who required intensive insulin therapy. It was not clear, however, whether the improved control of the blood glucose levels resulted in the prevention or progression of the diabetic complications. The risks of having adverse effects, such as diabetic ketoacidosis or hypoglycemia, were higher with CSII as compared with MDI; both methods having higher risks of these complications in comparison to conventional insulin therapy. CSII may be beneficial for patients requiring intensive insulin therapy who may need greater lifestyle flexibility with regard to meal timing, work, and recreational scheduling.