PURPOSE:We identified and treated young adults with type 1 diabetes who had been lost to follow-up during their transfer from pediatric to adult care, comparing their clinical, psychosocial, and health care utilization outcomes to participants receiving continuous care (CC) throughout the transition to adult care. METHODS:Individuals in their last year of pediatric care (CC group, n = 51) and individuals lost to follow-up in the transfer to adult care ("lapsed care" [LC] group, n = 24) were followed prospectively for 12 months. All participants were provided developmentally tailored diabetes education, case management, and clinical care through a structured transition program. RESULTS:At baseline, LC participants reported lapses in care of 11.6 months. Compared with CC participants, they had higher hemoglobin A1C (A1C; p = .005), depressive symptoms (p = .05), incidence of severe hypoglycemia (p = .005), and emergency department visits (p = .004). At 12-month follow-up, CC and LC participants did not differ on the number of diabetes care visits (p = .23), severe hypoglycemia (no events), or emergency department visits (p = .22). Both groups' A1C improved during the study period (CC: p = .03; LC: p = .02). LC participants' depressive symptoms remained elevated (p = .10), and they reported a decline in life satisfaction (p = .007). There was greater loss to follow-up in the LC group (p = .04). CONCLUSIONS:Our study suggests that, for young adults with a history of lapses in care, a structured transition program is effective in lowering A1C, reducing severe hypoglycemia and emergency department utilization, and improving uptake of routine diabetes care. Loss to follow-up and psychosocial concerns remain significant challenges in this population.