Langerhans cell histiocytosis (LCH) is a rare disease in which the most common endocrine manifestation is diabetes insipidus (DI). Data on anterior pituitary function in patients with LCH are limited. Thus, the present study investigated anterior pituitary function in LCH patients with DI via the evaluation of clinical and radiological findings at disease onset and during follow-up. The present study retrospectively evaluated nine patients with LCH (five males and four females). All diagnoses of LCH were made following histological and/or immunophenotypic analyses of tissue biopsies, bronchoalveolar lavage, or cerebrospinal fluid (CSF). Basal and, if necessary, dynamic pituitary function tests were used to assess anterior pituitary function, and magnetic resonance imaging (MRI) scans were used to image the pituitary. The LCH treatment modality was based on organ involvement. The mean age at onset of DI was 27.6 years (range 15-60 years). One patient (11 %) exhibited single organ involvement, while eight patients (89 %) displayed multisystem organ involvement. On admittance, one patient had hypogonadotropic hypogonadism, one patient exhibited panhypopituitarism [ hypogonadotropic hypogonadism, central hypothyroidism, hypocortisolism, and growth hormone (GH) deficiency], and four patients (44 %) displayed hyperprolactinemia. The MRI data revealed infundibular enlargement in seven patients (78 %), a thalamic mass in one patient (11 %), and the absence of the bright spot in all patients. A single patient (11 %) showed a mass in the pons that had a partially empty sella. The patients were treated with radiation therapy (RT), chemotherapy (CT), or a combination of both (RT + CT) and were followed up for a median of 91.8 months (range 2-318 months). Seven patients were assessed during the follow-up period, of whom four patients (57.1 %) developed anterior pituitary hormone deficiency, three (43 %) were diagnosed with GH deficiency, and one (14 %) exhibited gonadotropin deficiency. The gonadotropin deficiency in the patient, which was diagnosed on admittance, was resolved during the follow-up period. DI persisted in all patients, and the conditions of the seven patients who have remained on follow-up are stable. In the present study, patients with LCH exhibited altered function in the anterior pituitary as well as the posterior pituitary, which may be due to the natural course of the disease or the effects of treatment. The present findings indicate that anterior pituitary function should be assessed in LCH patients on admittance and during follow-up, especially in LCH patients with multisystem organ involvement.