An extension of our previous genome scan of a North American Holstein-Friesianpopulation was conducted to identify quantitative trait loci (QTL) affectingconformation traits. Resource families consisted of 1404 sons of 10 elite sires.Genome coverage was estimated to be 2713.5 cM (90%) for 406 markers using agranddaughter design. Regression interval mapping was used to detect QTLaffecting 22 conformation traits, including body, udder, feet and legs, anddairy conformation as well as calving ease. Analysis of the families jointlyidentified 41 chromosome-wise significant QTL influencing conformation traitsand 3 significant QTL influencing calving ease on 20 chromosomes. The falsediscovery rate method was used to account for multiple testing and 3/4 of thesuggestive and 5/6 of significant QTL should be real effects. Fourteen of the 44QTL were significant at the genome-wise level. Comparison of these results withother published reports identifies common QTL affecting conformation traits.Regions on 10 chromosomes appear to affect multiple traits, includingconformation, milk production, and somatic cell score, within these particularUS Holstein families. Additional work is needed to determine the preciselocations of the QTL and select positional candidate genes influencing thesetraits.