We have isolated an Agaricus bisporus cDNA which encodes an open reading frame of 130 amino acids. A comparison with the Genbank database shows that the deduced amino acid sequence of this open reading frame is highly homologous to the small subunit ribosomal proteins S15a of Brassica napus and Drosophila melanogaster and to the small subunit ribosomal proteins S24 of Strongylocentrotus purpuratus and Saccharomyces cerevisiae.