Two chicken genomic libraries were screened for the presence of poly(TG/AC) microsatellite tracts. The number of positive clones was low, confirming the low frequency of such microsatellites in the chicken genome relative to mammalian genomes. Polymorphism of 29 microsatellite tracts, comprising 11 from the library screening and 18 obtained from GenBank, was examined in the East Lansing and Compton reference families, in a resource population formed by a cross between a single White Rock broiler and inbred Leghorn females, and in a panel of birds from five layer stocks. Twenty microsatellites, primarily of the poly(TG/AC) type, were polymorphic in at least one of the populations. Thirteen of the microsatellites were polymorphic in the East Lansing reference family and 13 were also polymorphic in the resource population, confirming that the genetic distance between White Rock and White Leghorn is about as great as between Jungle fowl and White Leghorn. Only six microsatellites were polymorphic in the Compton reference family, formed by a cross between two White Leghorn strains. Twelve of the microsatellites were mapped in the East Lansing and/or Compton reference families. These were well dispersed among the various linkage groups and did not show any indications of terminal clustering.