PURPOSE: To determine the long term survival of patients with advanced ovarian cancer treated with radioimmunotherapy following cytoreductive surgery and platinum based chemotherapy. PATIENTS AND METHODS: Eligibility criteria included patients with histological evidence of ovarian cancer stages IC-IV following completion of conventional platinum containing chemotherapy. Of 52 patients entered into the study, 31 had residual disease following standard chemotherapy and 21 patients had achieved complete remission. Treatment consisted of one intraperitoneal administration of 25 mg of monoclonal antibody HMFG1 labelled with 18 mCi/m2 of 90Y. Survival was the primary end-point. RESULTS: In the group of 21 patients who had achieved complete remission following surgery, conventional chemotherapy and intraperitoneal radioimmunotherapy, the median survival has not been reached with a maximum follow-up of 12 years. Survival at greater than 10 years is 78%. CONCLUSION: This study suggests that a substantial proportion of patients who achieve complete remission with conventional therapy can achieve a long-term survival benefit when treated with intraperitoneal radioimmunotherapy using HMFG1 labelled with 90Y.