A quantitative trait locus (QTL) analysis of carcass composition data from athree-generation experimental cross between Meishan (MS) and Large White (LW)pig breeds is presented. A total of 488 F2 males issued from six F1 boars and 23F1 sows, the progeny of six LW boars and six MS sows, were slaughtered atapproximately 80 kg live weight and were submitted to a standardised cutting ofthe carcass. Fifteen traits, i.e. dressing percentage, loin, ham, shoulder,belly, backfat, leaf fat, feet and head weights, two backfat thickness and onemuscle depth measurements, ham + loin and back + leaf fat percentages andestimated carcass lean content were analysed. Animals were typed for a total of137 markers covering the entire porcine genome. Analyses were performed using aline-cross (LC) regression method where founder lines were assumed to be fixedfor different QTL alleles and a half/full sib (HFS) maximum likelihood methodwhere allele substitution effects were estimated within each half-/full-sibfamily. Additional analyses were performed to search for multiple linked QTL andimprinting effects. Significant gene effects were evidenced for both leannessand fatness traits in the telomeric regions of SSC 1q and SSC 2p, on SSC 4, SSC7 and SSC X. Additional significant QTL were identified for ham weight on SSC 5,for head weight on SSC 1 and SSC 7, for feet weight on SSC 7 and for dressingpercentage on SSC X. LW alleles were associated with a higher lean content and alower fat content of the carcass, except for the fatness trait on SSC 7.Suggestive evidence of linked QTL on SSC 7 and of imprinting effects on SSC 6,SSC 7, SSC 9 and SSC 17 were also obtained.