The gene coding for rat parathyroid hormone-like peptide (PTHLH) was previously assigned to rat chromosome 2 (Hendy et al., 1988). We reexamined this assignment. According to our results, the gene is on rat chromosome 4. Taking into account the known localizations of the KRAS2 (Kras-2) oncogene and the PTHLH gene, this assignment strongly suggests that a synteny group is conserved on rat chromosome 4, mouse chromosome 6, and human chromosome 12.