Objective: To evaluate the impact of structured transition from pediatric to adult inflammatory bowel disease (IBD) services on objective patient outcomes, including disease flares, admission rates, and healthcare resource use., Methods: A retrospective observational study in 11 United Kingdom gastroenterology centers. Transition patients attended ≥2 visits to the gastroenterology service with both pediatric and adult personnel jointly present; non-transition patients transferred to adult services without joint visits. Data were collected from medical records for the 12-month periods before and after the date of the first visit involving adult IBD services (index visit)., Results: A total of 129 patients were included: 95 transition patients and 34 non-transition patients. In the 12 months post-index visit, transition patients had fewer disease flares (P = 0.05), were more likely to be steroid-free (71% vs 41%, P < 0.05), and were less likely to have an emergency department visit leading to hospital admission (5% vs 18%, P < 0.05). During this period, the mean estimated overall cost of care per patient was £1644.22 in the transition group and £1827.32 in the non-transition group (P = 0.21)., Conclusion: Structured transition from pediatric to adult IBD care services was associated with positive and cost-neutral outcomes in patients with pediatric IBD., Competing Interests: Conflicts of Interest: S.M. has received honoraria for previous advisory board/meeting participation from AbbVie; and has served as a speaker, a consultant, and an advisory board member for AbbVie, Actavis, Falk, Ferring, Janssen, MSD, and Takeda. J.O.L. has served as a speaker, a consultant, and an advisory board member for AbbVie, Actavis, Ferring, Hospira, Janssen, MSD, Napp, Pfizer, Shire, Takeda, and Tillotts Pharma; and has received research funding from Hospira, MSD, and Shire. R.K.R. has served as a speaker, a consultant, and an advisory board member for AbbVie, Janssen, Pharmacosmos, Takeda, and Tillotts Pharma. D.R.G. has spoken/worked in an advisory capacity for AbbVie, Ferring, MSD, Takeda, and Vifor Pharma. I.S. has received honoraria for previous speaking/advisory board membership from AbbVie. C.D.M. has served as a speaker, a consultant, and an advisory board member for AbbVie, Falk, MSD, and Shire. T.F.-H. is an employee of AbbVie and may own AbbVie stock and/or options. S.S. has received research grants from Amgen, Ferring, MSD, Pfizer, Takeda, Tillotts Pharma, and Warner Chilcott; and has received sponsorship and advisory board and speaker honoraria from AbbVie, Celgene, Falk, Ferring, Janssen, MSD, Pfizer, Pharmacosmos, Takeda, and Warner Chilcott., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)