Mammary tumors are common in cats. As mutations in human Brca2 confer an increased risk of breast cancer, the full-length cDNA of the feline homologue of Brca2 was sequenced to obtain a basis for studying the relationship between its function and susceptibility to mammary tumors. The feline Brca2 cDNA is 10 kb long, and encodes 3,371 amino acids. The amino acid sequence of feline Brca2 shares low homology with the Brca2 of other mammals, e.g., 53% homology with the murine protein. Analysis of the expression pattern of the feline Brca2 gene revealed that, as previously reported for other mammals, it is transcribed in various tissues, including the mammary gland.