CC49 is a second-generation murine antibody with anti-TAG-72 (tumor-associated antigen) reactivity. For cancer therapy, it has the advantage of being expressed on adenocarcinomas but not on most normal tissues. CC49 has been utilized in phase I and II clinical trials at multiple institutions. Therapeutic applications to date have included 131I-, 90Y-, and 177Lu-CC49, with tracer amounts of 111In-CC49 as a dosimetry surrogate for 90Y-CC49 therapy. Dosimetry methods and details of their description vary between studies. Biodistribution to normal organs and the effective plasma T 1/2 for various radionuclides were relatively consistent among patients with different diseases and treatment at several institutions. As expected with marrow suppression being the dose-limiting toxicity, higher doses of 177Lu-CC49 were tolerated via intraperitoneal than IV administration. The biologic response modifier interferon enhanced TAG-72 expression and resulted in a trend of increased uptake of 131I-CC49 by tumors. Tumor dose estimates were more variable than that of normal organs. Standardization and improved dosimetry may be helpful for comparison among patients in various studies and for establishing dose/toxicity relationships that are useful for predicting safe levels of radioimmunoconjugates.