Studies on cytoreductive surgery for advanced ovarian and primary peritoneal cancer have consistently shown a strong correlation between cytoreduction and survival, with the best survival observed in patients who have no visible residual disease after successful cytoreductive surgery. Recent data that intraperitoneal chemotherapy further improves survival after optimal cytoreduction adds to the potential benefit of such surgery. More recently, significant survival benefit from optimal cytoreduction has also been shown for patients with recurrent disease and for women with advanced endometrial carcinoma. The selection criteria for patients and critical aspects of the operative technique and timing of cytoreductive surgery are discussed.