The aim of this project was to identify and characterize Quantitative Trait Loci for growth, composition, and meat quality in a three-generation cross between animals from Berkshire and Yorkshire breeds of swine. Specifically, the objective was to identify QTL with parental specific expression or imprinting, i.e. QTL that only have an effect if inherited from the sire (paternal expression) or dam (maternal expression). Many QTL were identified, of which several showed evidence of parental specific expression. Imprinted QTL were identified on chromosomes 1, 2, 5, 9, and 10, including QTL with paternal expression for backfat and loin eye area on chromosome 2, near IGF2, and QTL with maternal expression for drip loss and reflectance on chromosome 9. Knowledge of parental specific expression of QTL is important and enables the strategic use of such QTL in selection programs. For example, a paternally expressed QTL for backfat would enable development of sow lines that carry and express the fatness QTL, for increased reserves, but that would not pass this on to their terminal progeny. Thus, backfat in the terminal progeny would not be increased because the QTL is not expressed when inherited from the dam.