A QTL detection for feed intake and carcass traits was conducted in a back-cross population. Large White x Piétrain boars were mated with Large White dams to produce 16 sires families and a total of 717 progeny. A genome scan was conducted with 114 microsatellite markers spread on the 18 porcine autosomes, using interval mapping techniques and approximate likelihood ratio tests. High significative QTL (P < 0.01 for the chromosome) were detected for traits related to carcass composition and meat quality on chromosomes SSC 6, SSC 8, SSC 15 and SSC 17. For feed intake and feed efficiency, QTL were on chromosomes SSC 6, SSC 8 and SSC 9, significative at 5% on the chromosome. QTL effects were all between 0.20 and 0.35 σp. The QTL on SSC6 corresponds at least partly to the Halothane gene. On SSC 8, the association between feed intake and carcass quality in the chromosomic region was not detected before. Most chromosomic regions pointed out were already identified in other populations based on the Piétrain breed, and are different from Meishan x Large White crosses.