Nineteen patients who had a giant-cell tumor of the pelvis were managed from 1944 through 1989. Thirteen of the patients were in the third or fourth decade of life. The ileum was involved in thirteen patients; the pubis, in two; the ischium, in three; and the pubis and ischium, in one. Five patients who had an initial Stage-II (active) lesion were managed with curettage; in one of the five, a local recurrence developed at twelve months, and the other four had no evidence of disease from nine to forty-six years after the curettage. Eight patients who had a Stage-III (aggressive) lesion were managed with resection of most of the lesion followed by curettage of any remaining positive margins; four of the eight also received adjuvant irradiation. None of the eight had a local recurrence; six had no evidence of disease from eight to twenty-seven years after the operation, one died because of a metastatic post-radiation sarcoma thirteen years after the operation, and one was asymptomatic but had pulmonary metastases three years after the operation. Four patients who had a Stage-III recurrent local tumor when they were first seen were managed with hemipelvectomy, wide resection, resection and curettage, and curettage and arthroplasty (one procedure each). Three had no evidence of disease seven to twenty years after the operation and one had died because of a post-radiation metastatic osteosarcoma eight years after the operation. Two patients who had Stage-III disease were managed with external beam radiation alone. One had no evidence of disease twenty-six years later. The other had a recurrence one year later, which was treated with additional irradiation; a second recurrence was treated with curettage and bone-grafting. Twenty-eight years after the initial radiation treatment, this patient had no evidence of disease. External beam irradiation was used for a total of eight patients; a post-radiation sarcoma developed in two.