The MET3 gene of Saccharomyces cerevisiae was cloned and its restriction map was found to differ in the upstream region from an earlier published map (Cherest et al. Gene 34, 269-281, 1985) and nucleotide sequence (Cherest et al. Mol. Gen. Genet. 210, 307-313, 1987). Southern blot analysis of genomic DNA from strains S288C and FL100 (the genetic backgrounds from which these different copies of the gene had been cloned) showed that our clone from a S288C-based library had the same restriction map as the chromosomal DNA from both of the strains. Comparison of the nucleotide sequence of the two clones indicated that the earlier published clone probably represented a cloning artifact. In our clone, we found upstream of MET3, the nucleotide sequence of the TDH2 gene (Holland and Holland, J. Biol. Chem. 255, 2596-2605, 1980). The chromosomal orientation of the two genes was determined to be MET3-TDH2-CEN10.