The role of computed tomography (CT) in the evaluation of the gluteal region was assessed. Six cases of gluteal masses were studied preoperatively by CT; several were also studied with conventional radiographic methods, including barium enema, cystogram, and intravenous urogram. Our case material included an epithelioid sarcoma, Ewing's sarcoma, endodermal sinus tumor, cystic hygroma, neurofibromatosis, and a normal variant. The conventional radiologic studies were normal or demonstrated nonspecific soft tissue density mass effect. By comparison, CT, with its cross-sectional imaging capability, provided unique diagnostic information. CT depicted the presence and origin of a mass, provided tissue characterization, and showed the extent of the lesion, often demonstrating the gluteal mass as an extension of an intrapelvic lesion. CT was valuable in monitoring tumor response to therapy, detecting recurrences, and excluding normal variants as the cause for a gluteal mass. The information provided by CT was important in treatment planning.