All major recombination pathways in the yeast Saccharomyces cerevisiae require the RAD52 gene product. We have examined the effect of the rad52-1 mutation on spontaneous mitotic recombination between heteroalleles, and found that prototrophs are produced at frequencies significantly above reversion. This residual recombination occurs at a relatively uniform level at all of the loci examined. To help understand the role that RAD52 plays in mitotic recombination, we examined recombination between all pairwise combinations of six mutant alleles of the LYS2 gene. The rad52-1 mutation decreased the variation in amount of recombination between the various pairwise combinations as well as lowering the overall frequency of recombination. The reduced variation results in a different pattern of recombination in rad52-1 cells than in wild type. One interpretation of these results is that the RAD52 gene product, directly or indirectly, plays a role in the formation or the resolution of mismatches in heteroduplex DNA.