These guidelines for the management of patients up to 18 years with Langerhans cell histiocytosis (LCH) have been set up by a group of experts involved in the Euro Histio Net project who participated in national or international studies and in peer reviewed publications. Existing guidelines were reviewed and changed where new evidence was available in the literature up to 2012. Data and publications have been ranked according to evidence based medicine and when there was a lack of published data, consensus between experts was sought. Guidelines for diagnosis, initial clinical work-up, and treatment and long-term follow-up of LCH patients are presented. Pediatr Blood Cancer 2013;60:175–184. © 2012 The Authors. Pediatric Blood & Cancer, published by Wiley Periodicals, Inc.