Objective: The transition period between paediatric and adult medicine is associated with poor patient outcomes and important numbers of patients lost to follow up. Describe the cohort of patients in adult care who benefit from a new transition program based on case management approach. Design: A longitudinal study was led since September 2016 in a French University Hospital. Methods: Patients with any endocrine or metabolic disease diagnosed during childhood and transferred to adult care were included. The transition program includes 3 steps based on case management: liaising with paediatric services, personalising care pathways, liaising with structures outside hospital (General practitioner, educational and social sector). Results: The cohort included 500 patients with malignant brain tumour (n=56 (11%)), obesity (n=55 (11%)), type 1 diabetes (n=54 (11%)), or other disease (n=335 (67%)). They were aged 19 in median at transfer, sex ratio: 0.5. At 21 months of follow-up in median, 439 (88%) have regular follow-up in or outside the hospital, 47 (9%) have irregular follow-up (absence at the last appointment or no appointment scheduled within the time recommended), 4 stopped care on the doctor's advice, 4 died, 3 moved, 3 refused care. The program involved 9,615 case management acts, 7% of patients required more than 50 acts. Patients who required most of support are usually affected by a neuro-cognitive disorder and have social issues. Conclusions: The case manager addresses the complex needs of patients. With time, the cohort will provide unprecedented long-term results of patients with various conditions who went through transition.