Thirty-three muscles or muscle groups were separated from 25 Canada AA beef carcasses. Each of these muscles and muscle groups was subsampled, and the contents of moisture, fat, soluble hydroxyproline, insoluble hydroxyproline, and total hydroxyproline were determined. In addition, a 1-kg roast from each muscle or muscle group was used to determine thaw-drip losses, cooking times, and total cooking losses. Cooking times ranged from 51.0 to 111.3 min/kg (S.E.=2.90). Thaw-drip losses ranged from 1.26 to 10.05% (S.E.=0.40). Total cooking losses ranged from 21.51 to 33.26% (S.E.=0.70). Moisture content ranged from 666.4 to 761.8 mg/g (S.E.=0.23). Fat content ranged from less than 30 to 118.7 mg/g (S.E.=0.25). The amount of total hydroxyproline on a dry, defatted basis ranged from 17.8 to 117.4 μMol/g (S.E.=2.24). Insoluble hydroxyproline ranged from 15.2 to 101.9 μMol/g, (S.E.=1.70), and soluble hydroxyproline ranged from 2.1 to 30.9 μMol/g (S.E.=0.78). Percent soluble hydroxyproline ranged from less than 10 to more than 30% (S.E.=0.79). Such wide variation in cooking and chemical properties undoubtedly has a considerable impact on the palatability attributes and consumer acceptance of beef. However, greater understanding of the chemical composition of muscle will provide a basis for the development of technologies to enhance the palatability of individual muscles and muscles groups.