To determine the ability of recent systemic chemotherapy protocols to reduce the incidence of central diabetes insipidus (CDI) in Langerhans cell histiocytosis (LCH), 43 CDI cases that belonged to a cohort of 348 pediatric patients with multi-focal LCH who were treated with the JLSG-96/-02 protocols were analyzed. The overall incidence of CDI was 12.4%, but in 24 cases CDI was already present at the time LCH was diagnosed. Thus, CDI developed during or after systemic chemotherapy over a follow-up period of 5.0 (0.2-14.7) years in only 19 patients (5.9%), with 7.4% at 5-year cumulative risk by Kaplan-Meier analysis. In two cases, complete resolution of CDI was noted. Anterior pituitary hormone deficiency was detected in 13 cases, while CDI-associated neurodegenerative disease was observed in six cases. The JLSG-96/-02 protocol appears to effectively reduce the occurrence of CDI. However, novel therapeutic measures are required to reverse pre-existing CDI and to prevent CDI-associated neurological complications.