Complications (EDIC) Study (2), are celebrating the 30th anniversary since the start of the DCCT and 20th since the reporting of the DCCT primary results (3). During the past three decades, our understanding of the relationship between metabolic control and complications and the treatment of type 1 diabetes (T1D) has been transformed by the results of DCCT/EDIC. Most importantly, the long-term prospects for patients have dramatically improved with the adoption of intensive therapy designed to achieve near-normal glycemia as the standard of care of T1D. In this Perspective, we present an overview of the major scientific advances provided by the DCCT/EDIC Research Group, the resulting changes in therapy that have improved long-term outcomes in patients with T1D worldwide, and the challenges that remain.