Forty muscles from each of 20 beef carcass sides were used to perform Warner-Bratzler shear (WBS) force determinations for within and among muscle effects. The M. triceps brachii differed (P < 0.05) in WBS values between the caput longum and caput laterale, and the M. gluteobiceps differed (P < 0.05) in WBS values between the vertebral, cranial, and caudal portions. The M. trapezius did not differ between the pars cervicalis and pars thoracica. Larger muscles were evaluated for location effects within muscles. The M. pectoralis profundus, M. infraspinatus, M. triceps brachii (caput longum), psoas major, and M. semimembranosus all had significant location effects. Muscles were allocated into "very tender," "tender," "intermediate" or "tough" categories. Those muscles considered "very tender" (WBS < 3.2 kg) were the diaphragm (outside skirt or wing of diaphragm), M. spinalis, M. infraspinatus, M. iliacus, M. psoas major, M. serratus ventralis, M. biceps brachii, M. obliquus internus abdominis, and M. vastus medius. Muscles considered "tender" (3.2 kg < WBS < 3.9 kg) were the M. tensor fasciae latae, M. pectorales superficiales, M. teres major, M. longissimus lumborum, M. biventer cervicis, M, longissimus thoracis, M. splenius, M. subscapularis, M. rectus femoris, M. gluteus medius, M. gracilis, M. complexus, M, rectus abdominis, M, rhomboideus, and M, triceps brachii. Muscles classified as "intermediate" (3.9 kg < WBS < 4.6 kg) were the M. gastrocnemius, M. supraspinatus, M. gluteobiceps, M. obliquus externus abdominis, M. semitendinosus, M. adductor, M. vastus lateralis, M. deltoideus, M. latissimus dorsi, M. transversus abdominis, and M. semimembranosus. Muscles classed as "tough" (WBS > 4.6 kg) were the M. extensor carpi radialis, M. trapezius, M. brachialis, M. pectoralis profundus, and M. flexor digitorum superficial (hind limb). The diaphragm muscle was the most tender (WBS = 2.03 kg), and the M. flexor digitorum superficialis was the toughest (WBS = 7.74 kg). Tenderness, as measured by WBS, varied among and within bovine muscles, and knowledge of this variation allows for more appropriate use for specific purposes in the marketplace.