Microsatellite markers have been found to be abundant, evenly distributed, and highly polymorphic in a number of eukaryotic genomes. The objective of this study was to determine the utility of (TG)n microsatellites in the chicken. A chicken library enriched for (TG)n repeats was generated and 42 unique clones containing (TG)n microsatellites were identified and sequenced. The number of uninterrupted TG repeats ranged from 4 to 14 with an average of 7.8, which was considerably less than the number of repeats found in mammalian species. When primers designed to amplify across the (TG)n microsatellites were used in polymerase chain reactions (PCR) containing genomic chicken DNA, 19 of the 33 primer sets examined yielded polymorphisms in at least one of the three sets of chicken families: 15, 11, and 11 primer sets detected polymorphisms in the East Lansing (EL) reference population, the Compton (C) reference family, and between Line 63 and Line 72 chickens, respectively. The polymorphic microsatellite markers in the EL and C reference families were genetically mapped. Nine and seven mapped markers in the EL and C reference families, respectively, are polymorphic between Line 63 and Line 72, indicating that microsatellite markers will greatly enhance the ability to genotype specific loci of any chicken population.