We have sequenced a 42,500 bp stretch located on chromosome X of Saccharomyces cerevisiae between the genes MET3 and CDC8. This stretch contains 24 open reading frames (ORFs) of at least 100 amino acids. Ten of these correspond to previously published sequences, whereas of the 14 remaining ORFs, only one, GTD892, has significant similarity to proteins from yeast or other organisms. It may belong to the family of ubiquitin-protein ligases and be involved in the ubiquitin-dependent proteolytic pathway. In addition, three tRNA genes were recognized, two of which had not been hitherto localized.