DNA strand break repair by HR is mediated by genes of the RAD52 epistasis group. Rad52 protein plays central role in this process. It binds and anneals complementary ssDNA, self-associate to form multimeric rings, interacts with Rad51, and promotes nucleation of Rad51 onto ssDNA. Here, we show that Rad52 competes with Srs2 anti-recombinase in mediating Rad51-catalyzed strand exchange reaction through common interaction site on Rad51. The molecular mechanism of Rad52 function in homologous recombination together with the role of postranslational modification (SUMO-ylation) is discussed.