Type 1 diabetes is an autoimmune condition in which the pancreatic β cells that produce insulin are destroyed by the body's immune system. For 100 years, diet and insulin injections have been the only effective treatment. Recent advances have led to significant progress in our understanding of the pathogenesis of the disease and the interplay between the environment, components of the immune system, and the β cells that are targeted. This has led to new therapies that rebalance the immune system and finally offer the promise of a cure.