The results of CT and bone scintigraphy of eight patients with a histologically proven cystic ameloblastoma of the jaw are reviewed. CT imaging revealed unilocular and multilocular cystic lesions with well-defined thin cystic borders in all patients. CT also detected increased density in the bone marrow adjacent to the cystic radiolucent lesion, suggesting that the ameloblastoma had spread into the cancellous bone. Further, nuclear bone scans showed a doughnut-shaped pattern in all cases and radioactivity beyond the cystic wall, indicating intramedullary extension of the ameloblastoma. The use of these two modalities was found to be complementary in delineating the full nature and extent of the pathologic lesion.