The Diabetes Control and Complications Trial and the Stockholm Study have conclusively demonstrated that improving the blood glucose control in patients with insulin-dependent diabetes mellitus (IDDM) reduces the risk of developing retinopathy, nephropathy and neuropathy. Each patient with IDDM should be carefully evaluated for the appropriateness of institution of an intensive insulin treatment programme. In particular, the risk of severe hypoglycaemia must be considered and the goals modified if necessary to reduce the risk. Successful implementation of an intensive treatment programme requires an experienced healthcare team and a knowledgeable and well motivated cooperative patient. Several variations of intensive treatment programmes can be used, with no definite superiority of one treatment method over the others. Individualization is the key to success. Each programme has the same general principles. Regular insulin is used to control the postprandial glucose excursion and a slow infusion of regular insulin by a pump or injected intermediate or long-acting insulin is used to balance fasting glucose utilisation and production. The treatment will not be successful without self-monitoring of blood glucose by the patient and frequent adjustment of the insulin doses to compensate for variations in blood glucose levels, diet and activity. The treatment should be followed with quarterly glycated haemoglobin determinations and a regular follow-up plan. During follow-up the main challenge for the healthcare team will be to maintain motivation in the patient and to assist with behaviour modification. A detailed understanding of intensive treatment programmes may be beyond the skill of the average primary care physician, but any physician caring for patients with diabetes will benefit from an understanding of the general treatment principles outlined in this article.