The gene coding for the clofibrate-induced cytochrome P-452 has been isolated from a cDNA library and a full-length cDNA clone sequenced. The sequence was identical with that reported by Hardwick et al. [(1987) J. Biol. Chem. 262, 801-810] apart from the presence of an additional 75 nucleotides inserted adjacent to the 3'-end of the coding region. Northern blot analysis indicates that this is probably a consequence of differential splicing, which may be relevant to the tissue-specific regulation of this gene.