Carcass information was accumulated over 8 yr (1971 through 1978) on approximately 600 beef carcasses representing eight breeds and 62 different combinations of these eight breeds. Armour tenderometer readings were obtained at four locations of the wholesale loin. Warner-Bratzler shear readings were obtained from the longissimus, gluteus medius and semitendinosus muscles. Both tenderometer and shear values were recorded on the longissimus and gluteus medius muscles. These tenderness values, fat cover, percentage kidney fat, carcass weight, loin eye area, yield grade, quality grade, conformation and marbling were analyzed with a model that included genetic additive effects for each of the two sexes (steers and heifers) for each of the eight breeds involved and regression on expected percent breed heterosis for each sex. The estimated regression coefficients of tenderness on percent breed heterosis were almost always negative and mostly statistically nonsignificant. This indicates that crossbreeding will not result in less tender muscles. For the cooked muscles, steers were more tender than heifers. All Pearson correlations between tenderometer and shear values except one were not statistically significant. The correlations among the shear readings and among the tenderometer readings of the muscles were positive, medium in value and statistically significant. Loin eye area increased with percent breed heterosis. This increase was greater with heifers than with steers. Heifers had more marbling and higher quality grades.