The canine species, including wolf and jackal, have four digits on the hind limb. It was thought that an extra first digit on the hind limb, named dewclaw, was a hereditary defect. For genetically related canine pedigrees with 73 members with dewclaws, we carried out a genome-wide scan for linkage with microsatellites. With an assumption of autosomal dominant mode of inheritance, significant linkages were detected for the markers on canine chromosome 16. The maximum two-point lod score of 20.76 was obtained for the REN85M08/REN85N14 markers at a recombination fraction of 0.00. For efficient analysis of linkage, a revised order of the chromosomal markers was established by assigning all the existing markers from the previous linkage and radiation hybrid maps. A chromosome-wide haplotype analysis revealed the location of the dewclaw locus within a few centimorgan intervals delimited by the UCMCF12 and CXX876 markers. Canine chromosome 16 is known to have syntenic relationships with human chromosomes 4q, 7q, and 8p.