Two experiments were conducted to determine the effect of CaCl2 injection on round muscles obtained from Bos indicus bulls and late-castrate steers. In Exp. 1, the biceps femoris (BF) muscle from the left side of each of 15 bull carcasses was injected within 30 min postexsanguination with .3 M CaCl2 at 10% by weight while either intact (n = 8) on the carcass or after hot boning (n = 7). The right sides served as controls. In Exp. 2, the semimembranosus (SM) muscles from the carcasses of nine steers (castrated at 16 mo of age) were hot-boned within 30 min postexsanguination and one-half were injected with CaCl2 as described above. Hot boning had no effect (P greater than .05) on shear force values. Calcium chloride injection dramatically reduced shear force requirements at 1, 8, and 14 d postmortem compared with noninjected controls in both experiments. Cooking traits of the SM muscle were not affected (P greater than .05) by CaCl2 injection. However, BF muscles injected with CaCl2 required more (P less than .05) time to cook and had greater (P less than .05) cooking losses than BF controls. Calcium chloride injection of prerigor round muscles reduced aging time needed for normal tenderization to 1 d postmortem. Hot boning was successfully used in conjunction with CaCl2 injection to facilitate the injection process.