The mapping of the gene coding for human aldolase C has been studied using a specific cDNA probe and genomic blots from a panel of human-hamster somatic cell hybrids. The results show that the aldolase C gene is on chromosome 17. In situ experiments have restricted the mapping to the region 17cen----q21.1. Using the same panel of human-hamster somatic cell hybrids, we have confirmed the localization of aldolase A and B on chromosomes 16 and 9, respectively.