The surgical outcome for innominate giant cell tumors was reviewed in 7 patients; 6 (86%) were female patients and 1 (14%) was a male patient. The patients had an average age of 28.7 years (range, 16-42 years) and an average followup of 4.6 years (range, 2.0-7.3 years). Three tumors were in the ischiopubic region, 3 were acetabular, and 1 was iliosacral. The tumors ranged in size from 5 cm x 6 cm to 17 cm x 18 cm. All margins were intralesional. Reconstruction in 3 cases used osteoarticular acetabular allografts. The local recurrence rate was 3 of 7 (43%). Ischiopubic tumors accounted for all recurrences. Vascular invasion was seen in all patients who had a recurrence and only 1 patient without a recurrence. Patients with recurrences underwent subsequent resections and radiation therapy, and remain disease free at an average followup of 3.0 years (range, 0.8-4.2 years) after recurrence. There were no malignant, metastatic, or multicentric recurrences, and no patient died of disease or complications. Innominate giant cell tumor occurs most often in women and is associated with a high risk for local recurrence. Wide margins usually are not possible; intralesional margins are accepted in cases of limited accessibility or potential functional compromise.