Porcine liver proteome iTRAQ analysis enabled the confident identification of 880 proteins with a rate of false positive identifications of less than 5%. Proteins involved in energy metabolism, catabolism, protein biosynthesis, electron transport, and other oxidoreductase reactions were highly enriched confirming the central role of liver as the major chemical and energy factory. Comparative analysis with human and mouse liver proteomes demonstrated that 80% of proteins were common to all three liver proteomes. In addition, it was also demonstrated that both sex of the animal and introduction of a novel phytase transgene into the genome each affected around 5% of total liver proteome. After controlling the false discovery rate (FDR</=0.1) using the Storey q value only four proteins (EPHX1, CAT, PAH, ST13) were shown to be differentially expressed between genders (Males/Females) and two proteins (SELENBP2, TAGLN) were differentially expressed between two lines (Transgenic/Conventional pigs). Current analysis is the largest proteome analysis for pig and complements the more extensive human and mouse proteome projects.