Langerhans cell histiocytosis (LCH) is an uncommon group of disorders affecting mainly children and young adults. In children, pulmonary involvement occurs mostly in the disseminated forms; isolated pulmonary lesions are unusual. A retrospective study was undertaken on a group of 42 children diagnosed with LCH over a 19-year period. Eight children (19 %) had radiological evidence of pulmonary involvement. The lung lesions were either present at the time of diagnosis or, when appearing during the course of the disease, always coinciding with exacerbation or recurrence of the disease in other sites. Lung involvement did not appear to be an unfavourable prognostic factor. However, the toxic effects of treatment on the lungs might lead to important pulmonary sequelae.