Relationships between a number of split and internal carcass measurements and per cent yield of the carcass and its component cuts when trimmed in accordance with commercial standards were examined using a sample of 482 hog carcasses. Carcass length and weight were found to have low predictive value, accounting respectively for approximately 9 and 4% of the total variance in per cent yield of the trimmed lean cuts (ham, loin, picnic, and butt). Commercial grade explained approximately 27% of the variance in this trait and sex approximately 21%. The most useful predictors of per cent yield of lean cuts, and the proportion of total variance explained by each, were: per cent yield of trimmed loin, 83%; ratio of loin area to total back fat, 53%; total back fat, 54%; and per cent lean in the ham face, 43%. A regression equation combining total back fat, loin area, and per cent lean in the ham face explained 63%. Regression equations are provided and implications as regards commercial grading and carcass appraisal for progeny testing are discussed.