An analysis of 231 patients with stages I, II, and asymptomatic III ovarian cancer, studied in a prospective randomized-stratified trial, is presented. None of the stage IA patients with well-differentiated tumors have had disease relapses; one fourth of the patients with poorly differentiated tumors have had disease relapses throughout the peritoneal cavity. There is therefore little justification for pelvic radiation alone as postoperative therapy for stage IA ovarian carcinoma. For stage IB, II, and asymptomatic III presentations, patients with an incomplete initial pelvic operation had poor survival characteristics with all tested therapies. For patients in whom the operation was completed, abdominopelvic radiation was superior to pelvic radiation alone or followed by chlorambucil, with respect to long-term survival and control of abdominal disease. The effectiveness of abdominopelvic radiation was independent of stage or histology. The value of abdominopelvic radiation was most strikingly seen in patients with no visible residual tumor.