Background. To develop salvage therapy for persistent/recurrent ovarian cancer confined to the abdominal cavity after standard treatment. Methods. High-affinity anti-TAG-72 antibody CC49 radiolabeled with 177Lu was given via intraperitoneal (IP) administration as a single agent or with human recombinant interferon alpha(subcutaneous) ± IP Taxol. IP administration for peritoneal implants confined to the abdominal cavity has the advantage of higher concentration of active agent at tumor deposits with less toxicity to the bone marrow from system absorption. Eligible patients had TAG-72 expressing tumor limited to the abdominal cavity after laparotomy-chemotherapy, ECOG performance status ≤ 2, adequate organ function and free flow of fluid in the peritoneal cavity. Results. IP 177Lu-CC49 alone was well tolerated in 27 patients with the only Grade 3-4 toxicity being transient bone marrow suppression (dose limiting at 45 mCi/m2). Tumor/marrow radiation ratios of 58-139 were obtained. One of 12 patients with gross disease measurable by CT had an objective response and 3 patients with small volume disease have remained without evidence of relapse at 3+-5+ years. More objective responses have been noted with adjuvant interferon ± Taxol. Observation continues in order to determine if there will be an improvement in relapse free survival for patients with non-measurable disease when adjuvant interferon + Taxol are used. Conclusions. Intraperitoneal radioimmunotherapy with 177Lu-CC49 alone or with adjuvant interferon ± Taxol has shown anti-tumor efficacy and extended relapse free survival in patients who have failed standard therapy.