The 1,728 base pair coding region of theILV1 gene and the adjacent 777 base pair upstream and 261 base pair downstream regions were sequenced. The size of the polypeptide deduced from the coding region is larger than previously determined values for the molecular weight of threonine deaminase, suggesting that a peptide with a molecular weight of about 15,000 is cleaved off in connection with the intracellular processing of the enzyme. In front of the gene are found three copies of the element TGACT charactenstic for genes under general amino acid control. Two of the coples are present in an orientation which is reversed to that found in front of other genes. Sites which potentially can bind strongly to the 3′-end of yeast 18 S ribosomal RNA are present at positions-S and-24 from the start of the coding region. An open reading frame of 31 codons is found in front of the gene. Its translation initiator codon is located at the center of a 151 base pair imperfect tandem inverted repent which in a single-stranded nucleic acid would fold into a stem structure with a ΔG of about-33 kcal·mole1. The biological significance of this arrangement is unknown.