This was a Phase I/II, single-center, dose-escalation study. 177-Lutetium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-cG250 (177-Lu-DOTA-cG250) was administered at a starting dose of 30 mCi/m^2 of 177-Lu (fixed dose of 10 mg cG250) and escalated in increments of 10 mCi/m^2 of 177-Lu in sequentially enrolled cohorts according to a standard 3 + 3 design until determination of the maximum tolerated dose (MTD). The primary objectives were to determine the safety, targeting, and dosimetry of 177-Lu-DOTA-cG250 in subjects with advanced renal cell carcinoma. The secondary objective was measurement of tumor response according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0.