A radioimmunoconjugate comprised of girentuximab conjugated with the bifunctional, macrocyclic chelating agent tetra-azacyclododecanetetra-acetic acid (DOTA) and lableled with the beta-emitting radioisotope yttrium Y 90. The antibody moiety of yttrium Y 90-DOTA-girentuximab binds to renal cell carcinoma cells expressing the G250 antigen, thereby selectively delivering a cytotoxic dose of beta radiation.