The yeast RAD52 protein is required for both homologous DNA recombination and repair of DNA double-strand breaks. RAD52 can bind to the yeast RAD51 protein, which shares a functional similarity with the bacterial RecA protein. The gene encoding the human homolog of the yeast RAD52 protein shares significant N-terminus amino acid homology with the yeast RAD52 protein. Using a yeast two hybrid system and purified GST-RAD52 fusion protein, we demonstrate that the human RAD52 protein self-associates both in vivo and in vitro. The region of RAD52 required for its self-interaction, mapped here as amino acid residues 65-165, has significant homology with the yeast RAD52 (52% identity, and 89% similarity), suggesting the importance of self-association for RAD52's function.