Plain radrographs of thirty nine patients with giant cell tumor of long bone and CT scans of twenty patients among the thirty patients were reviewed retrospectively to evaluate the frequency and significance of sclerosis of the tuor margin, The sclerosis of the tumor margin was observed on plain radiographs in thirteen patients (33.3%) and they were located either on epiphyseal or on both epiphyseal or metaphyseal portion at the tumor. The authors concluded that the giant cell tumor should not be excluded from the differential entities eventhough the tumor has the marginal sclerosis.