A cDNA clone of Xenopus laevis, designated Xhox3.1 was cloned by using mouse Hox3.1 cDNA as a probe. It was found that Xhox3.1 cDNA consisted of 1,760 bp and the base composition was 525 adenines, 384 cytosines, 373 guanines, 487 thymines. The cloned cDNA did not contain a full length sequence missing approximately 300 bp of 5'-upstream region. However, it contained several important motifs such as a homeobox domain (nt. 316-419), a hexapeptide conserved region (nt. 283-300) and a polyglutamic acid stretch (nt. 526-588). Sequence comparison between Xhox3.1 and mouse Hox3.1 revealed a 98% homology in amino acid and 77% in nucleic acid sequence in a homeobox domain. And the sequence homologies of amino acid and nucleic acid in hexapeptide which was located in the upper region of homeodomain were 100% and 94%, respectively. As other homeobox genes, Xhox3.1 had a 3'-untranslated region in which transcription regulatory sites located.