During the last quarter of a century continuous subcutaneous insulin infusion (CSII) with external portable insulin pumps has been increasingly used in selected type 1 diabetic subjects and also in some patients with type 2 diabetes mellitus. The treatment of diabetes mellitus with insulin pumps has become more and more popular and accepted by diabetic patients as well as by medical professionals worldwide. Published trials have shown that, in most patients, mean blood glucose concentration and glycated hemoglobin (HbA1c) percentages are either slightly lower or similar on CSII versus an optimized therapy with multiple daily insulin injections. Hypoglycemic episodes seem to be less frequent and ketoacidoses occur at a comparable rate to that during intensive injection therapy. Moreover, nocturnal glycemic control can be improved with insulin pumps, and automatic basal rate changes help to minimize a prebreakfast blood glucose increase (often called 'the dawn phenomenon'). For many patients, CSII provides greater flexibility in timing of meals with the result of better quality of life and higher treatment satisfaction. However, despite these promising data, and although many patients with diabetes mellitus with well-defined clinical problems are likely to benefit substantially from CSII, either in respect to glycemic control, acute complications or quality of life and treatment satisfaction, we are still far away from reaching'dream diabetes management', the fully automatic closed-loop system. Presently, the most difficult problem concerns not the design of an 'optimal' insulin pump, but rather the development of a system which is able to provide continuous and reliable blood glucose monitoring. Hence, because this problem has not been solved with maximum satisfaction, the development of a feedback-controlled 'artificial pancreas' is one of the main goals in diabetes management in the new millennium.