To explore the ability of magnetic resonance imaging (MRI) in the diagnosis of avascular necrosis (AVN) of the femoral head, we compared appearances on MRI of 85 proven AVN lesions with those on radiographs (n=79) and radionuclide scans (n=75) Clinical symptoms(n=85) were also correlated. All MR studies included coronal and axial TIWI and coronal T2WI, All lesions involved the anterosuperior aspect of the femoral head nad were surrounded by a low signal intensity rim on both T1 and T2WI. The signal intensity of the lesions was variable depending on the disease course, and the leions were divided into four classes according to the class A(10), B(1), C(2) The radionuclide scans showed normal in 16%(12/75) of the lesions which were in MR class A(8), B(1), C(2) D(1) On the other hand, 93% of the lesions with MR class A(27/29) showed stage 1 and 2 lesions on radiographs. Clinical symptoms were absent in 25%(21/85) of the leions, and . among these, 81%(17/21) were MR class A. Conclu ively, MR is superior to the radiograph and radionuclide scan in the early detection of AVN, and can also show the exact location, extent and signal chansacteristics of the lesion, Therefore. MR is essential in diagnosis and management of AVN.