A prospective, stratified, randomized study of 190 postoperative ovarian patients with Stages IB, II, and III (asymptomatic) presentations is reported. The median time of follow-up was 52 months. Patients in whom bilateral salpingo-oophorectomy and hysterectomy (BSOH) could not be completed because of extensive pelvic tumor had a poor prognosis which did not differ for any of the therapied tested. When BSOH was completed, pelvic plus abdominopelvic irradiation (P + AB) with no diaphragmatic shielding significnatly improved patient survival rate and long-term control of occult upper abdominal disease in approximately 25% more patients than pelvic irradiation alone or followed by adjuvant daily chlorambucil therapy. The effectiveness of P + AB in BSOH-completed patients was independent of stage or tumor grade and was most clearly appreciated in patients with all gross tumor removed. Chlorambucil added to pelvic irradiation delayed the time to treatment failure without reducing the number of treatment failures.