Using described criteria for the selection of patients for excision or resection of tumors involving various portions of the innominate bone, as opposed to hemipelvectomy, fifty-seven out of the more than 200 patients evaluated were judged to be candidates for a curative procedure. Of these, twenty-five were selected for hemipelvectomy and thirty-two, for non-amputative procedures. Depending on the location and extent of the lesion as determined by complete preoperative work-ups, three types of procedures were performed singly or in combination:(1) wide excision or radical resection of the iliac wing; (2) periacetabular wide excision or radical resection; or (3) wide excision or radical resection of the pubis. Reconstruction was accomplished when the hip joint was excised by fusion or the creation of a pseudarthrosis either medially in relation to the pubis or laterally in relation to the ilium or wing of the sacrum. The results after follow-ups of one to seventeen years were assessed in terms of the immediate goals of surgery, control of the disease, and function. The findings were as follows: With the preoperative assessment and operative techniques described, an oncologically adequate procedure was performed in two-thirds of the cases. In the remaining cases, the adequacy of the procedure was compromised by poorly planned biopsies, occult microextensions, and surgical errors. The recurrence rate was high after the inadequate procedure (100 per cent) and low (4 per cent) after the adequately accomplished procedures. Function was nearly normal when the hip joint was preserved. If the hip joint was removed and fusion was obtained, the results were good, but fusion was obtained in only 50 percent of the cases in which it was attempted. If the hip joint was removed and pseudarthrosis resulted, the results ranged from good to poor. Sciatic-nerve involvement necessitating resection of the nerve was not a contraindication to a non-amputative procedure.