A second copy of the Saccharomyces cerevisiae ribosomal protein YL19 gene was isolated through the use of the RPL19A gene as a probe. The nucleotide sequence of the gene, RPL19B, was determined. RPL19B contains an intron of 384 nucleotides located near its 5'-end. The coding regions of the two yeast genes, RPL19A and RPL19B, differ in only 34 nucleotides, none of which lead to changes in the amino-acid sequences of the predicted protein of 189 amino acids. RPL19B is also closely linked to a mitochondrial ADP/ATP carrier protein gene AAC2. Yeast cells containing disruption of either RPL19A or RPL19B formed smaller colonies than wild-type strains; however, simultaneous deletion of both genes is lethal.