Objective: To evaluate the effect of a new care organization on multiple outcomes of transition success and its cost-effectiveness in patients with any endocrine or metabolic disease diagnosed during childhood and transferred to adult care.Design: Non-randomized controlled trial in a French university hospital.Methods: Patients transferred to adult care during the control period (04/2014-08/2016) and the intervention period (09/2016-06/2018) were included. The intervention is based on case management involving liaising with pediatric services, personalizing care pathways, and liaising with structures outside hospital (general practitioner, educational and social sector). The primary endpoint was the percentage of patients lost to follow-up at 24 months post transfer. Other outcomes were collected from medical files, consultation software, and questionnaires. A cost analysis was performed.Results: Two hundred two patients were included (101 per period), the most represented pathologies were congenital and non-congenital hypopituitarism (respectively n= 34 (17%) and n= 45 (22%)) and thyroid diseases (n= 21, 10%). Patients were aged 22.5 in median at 24 months post transfer where 12 were lost to follow-up in the control group vs 9 with the intervention (P=0.49). The percentage of honored consultation among those planned during 24 months was higher with intervention (P=0.0065). Patient satisfaction, physician trust, and transfer delay did not differ between the groups. The incremental cost-effectiveness ratio was Euro179 per patient not lost to follow-up.Conclusions: At 24 months post transfer, the rate of lost to follow-up did not differ significantly, but indicators of a steadier follow-up were increased and the intervention appeared to be cost-effective.