The DCCT study confirmed the importance of optimizing insulin therapy to reduce the microvascular risks of diabetes mellitus. Optimization requires improving the methods already in use. Recent results must be used to improve patient motivation. Control of blood glucose levels must include improving the frequency and/or the quality of follow-up (pluridisciplinary consultations). Follow-up must be improved, taking advantage of the recent developments such as rapid glycosylated haemoglobin assay and computerized glucose meters. Of course, improvement in blood glucose must aim at normal levels, accepting the increased risk of hypoglycaemia. The insulin-tool itself must be improved on the basis of recent developments including ultra-rapid analogues and external and implantable insulin pumps. Finally, a major challenge is to develop these improvements without increasing too greatly the patient's short-term costs and without causing further discomfort.