Primary tumors of the sacrum are rare. Some lesions of low or latent malignancy are curable by extensive or subtotal resection. Among the 14 cases reported in this article the majority were giant-cell tumors and chordomas. Extensive resection was done for 2 of the 5 giant-cell tumors and no recurrence was seen for 7.5 and 21 years respectively. The other 3 cases were treated with local resection or radiotherapy alone; all died within 1 year. Total or subtotal resection were done for the other tumors. The operative procedure was described in detail. The pelvic stability and the function of urinary bladder and rectum following the operation were discussed.