Using a human tyrosinase cDNA probe, we have isolated mouse tyrosinase genomic clones and used them to map the mouse tyrosinase locus and to analyze the promoter sequence of the tyrosinase gene. Southern blot analyses of DNA from somatic cell hybrids, interspecies backcross mice, and albino deletion mice have revealed that the locus for mouse tyrosinase resides at or near the albino locus on mouse chromosome 7. There were three TATA-elements, but only one CAT-element, and the CAT-element appeared to be paired with the third TATA-element, located at the position farthest upstream. Mouse tyrosinase mRNA is approximately 2.4 Kb in size. The amount of tyrosinase mRNA reflects the levels of tyrosinase activity in normal melanocytes and Cloudman S-91 melanoma cell line.