The Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) trial demonstrated that glycemic failure rates were significantly lower in youth randomized to metformin plus rosiglitazone treatment than in youth randomized to metformin alone or metformin plus intensive lifestyle intervention. At the end of the study, rosiglitazone was permanently discontinued, and routine diabetes care resumed. Herein, we report postintervention glycemic failure rates in TODAY participants over an additional 36 months of follow-up for the three original treatment arms and describe insulin sensitivity and β-cell function outcomes.A total of 699 participants were randomized during TODAY, of whom 572 enrolled in the TODAY2 observational follow-up. Glycemic failure was defined as HbA1c ≥8% over a 6-month period, inability to wean from temporary insulin therapy within 3 months after acute metabolic decompensation during TODAY, or sustained HbA1c ≥8% over two consecutive visits during TODAY2. Oral glucose tolerance tests were conducted, and insulin sensitivity, insulinogenic index, and oral disposition index were calculated.During the 36 months of TODAY2, glycemic failure rates did not differ among participants by original treatment group assignment. Insulin sensitivity and β-cell function deteriorated rapidly during the 36 months of TODAY2 routine diabetes care but did not differ by treatment group assignment.The added benefit of preventing glycemic failure by using rosiglitazone as a second agent in youth-onset type 2 diabetes did not persist after its discontinuation. More work is needed to address this rapid progression to avoid long-term diabetes complications.