Human cDNA probe H1.6 (clone 10-1) encoding cystic fibrosis transmembrane conductance regulator (CFTR) was used to map the bovine homolog of CFTR. Using a panel of bovine x rodent hybrid somatic cells, the homolog was mapped to bovine syntenic group U13 which corresponds to chromosome 4. CFTR is 97.7% concordant with syntenic markers T-cell receptor beta (TCRB) and P-glycoprotein 3 (PGY3). The comparative gene maps of CFTR, TCRB, and PGY3 on human chromosome 7, bovine chromosome 4, and mouse chromosome 5 and 6 indicate conservation of synteny, although internal rearrangements relative to HSA 7 are present in both cattle and mice.