Mechanical deboning yields meat containing approximately 0.5% calcium. The bioavailability of the calcium in mechanically deboned meat ( MDM ) was compared to that from calcium carbonate fed in hand deboned meat ( HDM ) diets. Processing calcium carbonate with HDM into bologna, Thuringer or canned meat improved calcium bioavailability but did not increase the bioavailability of the calcium from MDM . The calcium absorptions were 62.7, 60.4 and 60.6%, respectively, from raw MDM , MDM bologna, MDM Thuringer and canned MDM . However, the percentage of calcium absorbed from calcium carbonate was increased slightly from 65.3, 65.9 and 65.6%, respectively, when it was processed as raw HDM , HDM bologna and Thuringer to 69.0% when processed as canned HDM . The bioavailability of the calcium in MDM was similar to that of calcium carbonate, whether expressed as apparent absorption or as relative biological value.