The p53 gene codes for a nuclear protein that has an important role in normal cellular replication1-4. The concentration of p53 protein is frequently elevated in transformed cells1,2. Transfection studies show that the p53 gene, in collaboration with the activated ras oncogene, can transform cells5-7. Chromosomal localization may provide a better understanding of the relationship of p53 to other human cellular genes and of its possible role in malignancies associated with specific chromosomal rearrangements. A recent study mapped the human p53 gene to the long arm of chromosome. 17 (17q21-q22) using in situ chromosomal hybridization8. Here, by Southern filter hybridization of DNAs from human-rodent hybrids, we have localized the p53 gene to the short arm of human chromosome 17.