We have determined the nucleotide sequence of the yeast CAR1 gene along with its 5' and 3' flanking sequences. The structural portion of this gene encodes a protein of 333 amino acid residues with a calculated Mr value of 35,616. The transcripts produced from this gene are modestly heterogeneous at their 5' and 3' termini. Most 5' termini map to a position 42 to 49 base pairs upstream from the ATG at the beginning of the open reading frame. The 3' termini map to a position 108 to 127 base pairs downstream of the amber codon which terminates the open reading frame. A variety of potentially significant sequences were identified in the regions flanking the structural portion of the gene.