The shear properties of raw and cooked beef and their relationship with Wamer-Bratzler (WB) tenderness measurement were evaluated.: Shear tests were performed on four muscles, biceps femoris (BF), longissimus dorsi (LD), semimembranosus (SM), and semitendinosus (ST), with three different aging treatments (0, 1, and 2 weeks), using a specially designed device and:the WE shear device. Raw beef exhibited a nonlinear behavior characterized by linearity at small deformations, stress yield at intermediate deformations, and work hardening at large deformations. Cooked beef had a different nonlinear behavior with the slope of the force-displacement curve increasing with displacement before the peak force. Cooking resulted in a large increase (p=0.01) in maximum shear force and strain energy. The effect of muscle type and aging on shear:properties was mostly significant (p=0.05). The maximum shear force of cooked beef was correlated with WE measurement with the R-2 value ranging from 0.65 to 0.34 for LD, SM, and BF except for ST with a R-2 value of 0.10. Correlations of the shear properties of raw meat with WE measurement were low (R-2 < 0.36) indicating the difficulty of predicting WE tenderness from the shear properties of raw meat.