In the presence of persistent or recurrent otorrhea with or without hearing impairment, a chronic infection of the middle ear should be suspected. Otoscopy is performed to distinguish between the less serious central perforation of the tympanic membrane and the peripheral bone-eroding infection, cholesteatoma. The diagnosis is purely clinical. Prior to an operation, a hearing test, radiography of the mastoid air cells and treatment of any infection are a must. Central perforation of the tympanic membrane is a relative indication for surgery, while in the case of a cholesteatoma complete removal of the process is mandatory to avoid potentially serious complications. Reconstruction of the ossicles takes second place in importance to complete removal of the cholesteatoma. All patients with this condition--in particular children--should be kept under surveillance over the long term.