The concept of eosinophilic granuloma is of rather recent origin and was named by Lichtenstein and Jaffe, in 1940 as a new and interesting entity of unknown origin, although they suggested the possibility of a virus etiology. In 1952, Harris and Spencer reported a case of a 3-year-old girl who suffered from eosinophilic granulomas of both mastoids. Eosinophilic granuloma is the localized variety of histiocytosis X manifested by single or multiple isolated bony lesions and carries a favorable prognosis. Recently, the authors experienced a case of eosinophilic granuloma of the temporal bone. The patient, 10 year-old male child, was admitted through OPD with both intermittent otorrhea and hearing impairment. Law's view revealed a cholesteatoma like large oval radiolucent defect of the right mastoid and cloudiness of the left mastoid air cells. Then it was treated as surgical procedures (tympanoplasty with mastoidectomy) and x-ray therapy with good result. Now, after follow up study of 11 months, patient has good ear findings with improved hearing.