Endocrinology has recently witnessed several important developments: The Epidemiology of Diabetes Interventions and Complications study, a follow-up to the landmark Diabetes Control and Complications trial, found that strict glucose control early in the course of type 1 diabetes reduces the risk of microvascular and cardiovascular complications and provides prolonged benefits even if intensive control is not so tightly maintained. Inhaled insulin preparations are now available for mealtime coverage. We now have two new injectable medications for diabetes; pramlintide (Symlin) and exenatide (Byetta) are good adjuncts for patients with both type 1 and type 2 diabetes who have trouble reaching their hemoglobin A1c target, and they can help control and even reduce weight. Thyroxine (T4), instead of being merely a "prohormone," has been found to have direct actions on cells, leading to rapid clinical effects and possibly oncogenesis and angiogenesis. The therapeutic range for thyrotropin (TSH) may be much narrower than traditionally believed: some have proposed that the normal range should be redefined as 0.4 to 2.5 mIU/L. New evidence shows that vitamin D is important for more than calcium control and may help prevent type 1 diabetes.