DNA polymerase beta (pol beta) is an enzyme possessing both polymerase and deoxyribose phophatase activities. Although pol beta is not believed to participate in the replication of genomic DNA, several studies have indicated a role for pol beta in DNA repair. The high level of expression of pol beta in mouse and rat testes raises the possibility that pol beta participates in mammalian meiosis. Using antibody localization, we detect foci that stain with pol beta antisera at discrete sites along homologous chromosomes as they synapse and progress through prophase of meiosis I. These data suggest that pol beta participates in meiotic events associated with synapsis and recombination.