Intraperitoneal chemotherapy and cytoreductive surgery have been combined to reach treatment objectives in patients with peritoneal carcinomatosis or sarcomatosis that neither modality by itself can achieve. These treatments must be combined with the proper selection of patients in order to observe "high value" results from therapy. There are three principles of management to support treatments for peritoneal carcinomatosis and sarcomatosis. First, the clinician must select patients who have isolated disease distributed on the surfaces of abdominal and pelvic structures. Patients treated for peritoneal implants who have persistent disease at other sites will profit little or not at all. Second, this disease must be reduced to its lowest possible mass by peritonectomy procedures and resections of viscera. Third, maximal intraperitoneal and systemic chemotherapy are utilized to eradicate the disease on peritoneal surfaces as well as control the primary or recurrent tumor. These principles of management and a presentation of the results achieved to date are reviewed.