Atraumatic avascular necrosis of the femoral head is a well-known disease which in the majority of cases is associated with conditions like alcohol abuse or steroid therapy. Early diagnosis is important, in particular in younger patients, in order to preserve the femoral head. Plain radiography, computed tomography, scintigraphy, and magnetic resonance imaging are the radiological methods used for detection of avascular necrosis, and especially magnetic resonance imaging has like scintigraphy been found to be well suited for diagnosis in early stages. Characteristic magnetic resonance scan patterns are described. Surgical treatment is necessary in most cases. Various methods are used, according to the stage of the disease.