Langerhans cell histiocytosis (LCH) is a rare, proliferative disorder which is characterized by proliferation of pathological Langerhans cells within different organs. In 90% of cases the head and neck are affected. In this article, we report a 2.5-year-old boy with LCH who was referred to the pediatric department of Babol Dental School, with a chief complaint of fever, mucosal ulceration, gingival necrosis and tooth mobility. Our clinical diagnosis was Langerhans cell disease. In panoramic radiography, multiple well-defined radiolucencies were observed in both maxilla and mandible. Histopathological examination confirmed our diagnosis. The patient underwent chemotherapy with vinblastine for one year. Oral manifestations are common findings in LCH, therefore, dentist plays an important role in both diagnosis and management of this disease.