One hundred and one new dinucleotide repeat polymorphisms specific for the canine genome have been identified and characterized. Screening of both primary libraries and marker-selected libraries enriched for simple sequence repeats led to the isolation of large numbers of genomic clones that contained (CA)n repeats. Over 200 of these clones were sequenced, and PCR primers that bracket the repeat were developed for those that contained ten or more continuous (CA)n units. This effort led to the production of 101 polymorphic markers, which were assigned to one of four categories depending on their degree of polymorphism. Fifty-four markers were found to be highly or very highly polymorphic as they had four or more alleles when tested on a panel of unrelated dogs. This group of markers will be useful for following inheritance of traits in crosses between dogs.