A joint analysis of two F2 crosses between commercially relevant breeds, Berkshire x Yorkshire, and Berkshire x Duroc, was conducted to identify chromosomal regions (quantitative trait loci or QTL) associated with growth, composition, and meat quality traits for four chromosomes. Joint analysis led to greater power to detect QTL, greater QTL mapping precision and better characterization of QTL. This enables proper definition of QTL in terms of inheritance mode of gene action and of segregation of alleles within the parental breeds, which provides valuable information for subsequent QTL analyses and marker-assisted breeding schemes. Because the populations studied were derived from commercially relevant breeds, the QTL identified have important economic effects for pork production.