Homeobox genes encode a family of transcription factors that have essential roles in regulating the development of eukaryotes. Although they have been extensively studied in different phyla, relatively little is known about homeoboxcontaining genes and their function in molluscs. In this study, we used a polymerase chain reaction to investigate homeobox genes in the bivalve mollusc Pecten maximus. Four different homeobox sequences were identified; two were homologues of the non-Hox cluster gene caudal and the two remaining sequences had a significant homology to the ANT-C gene Proboscipedia. These sequences represent the first cad and pb homologues isolated from a member of the class Bivalvia, phylum Mollusca.