Osteoarthritis (OA) is a very common bone and joint disease characterized by breakdown of cartilage in the joint. We recently found that an aspartic-acid repeat polymorphism of the asporin gene (ASPN) on chromosome 9 is associated with susceptibility to OA in Japanese. We provide here a high-resolution single nucleotide polymorphism (SNP) map within a 33.4-kb genomic region containing ASPN. A total of 19 SNPs were isolated from the region by systematic screening using 48 Japanese patients with OA: 7 SNPs in the 5' flanking region, 8 in introns, and 4 in the 3' untranslated region. Nine SNPs were novel. This high-resolution SNP map will be a useful resource for analyzing genes associated with OA and other bone and joint diseases.