A 2810 bp DNA fragment containing the beta-isopropylmalate dehydrogenase gene of the dimorphic yeast Yarrowia lipolytica has been sequenced. The sequence contains an open reading frame of 405 codons, predicting a protein of 43,366 molecular weight. Protein sequence homology with the polypeptide encoded by the LEU2 gene of Saccharomyces cerevisiae is 64%, whereas DNA sequence homology is 61%. The 5'- and 3'-flanking regions of the Y. lipolytica LEU2 gene share only some general structural features common to genes of S. cerevisiae such as the presence and location of TATA boxes, CAAT boxes, CACACA repeats, the lack of G residues in the 5'-untranslated region and 3'-transcription terminators. Transcription of a 1.4 kb mRNA begins at a small cluster of sites approximately 40 base pairs before the initial ATG.