Beef carcasses (n = 1574) were evaluated at Excel Corp. beef slaughtering facility, Friona, Texas, to determine the effects of implants (double Revalor and Ralgro/Revalor) and biological type (Continental European, Continental European × British and British) on carcass characteristics. No differences (P > 0.05) were found between implants for marbling score, USDA quality grade, adjusted preliminary yield grade, percentage kidney, pelvic and heart fat, or carcass weight. Carcasses from cattle implanted with double Revalor had a larger (P < 0.05) ribeye area and a lower USDA yield grade. No differences were found among breed types for marbling score, USDA quality grade, preliminary yield grade, ribeye area or USDA yield grade (P > 0.05). Steers classed as continental European had the lowest adjusted preliminary yield grade and percentage kidney, pelvic and heart fat, the heaviest carcasses and were most muscular as determined by the Excel muscle score (P < 0.05).