A cosmid clone bank of yeast DNA has been used to isolate the cycloheximide resistance gene cyh2 of Saccharomyces cerevisiae. A cosmid carrying this gene was identified by cross hybridization to another cloned gene, tsm437. The two genes, which are tightly linked genetically are both present on a 31 kb segment of cloned DNA. The cyh2 gene encodes ribosomal protein L29, a component of the large subunit. Blot hybridization analysis reveals that this gene is present as a single copy in the yeast genome, unlike many other yeast ribosomal protein genes which appear to be duplicated. The cyh2 gene also appears to contain an intervening sequence, a characteristic common to most yeast ribosomal protein genes that have been cloned.