The Xeroderma pigmentosum complementation group A (XPA) protein that is indispensable for nucleotide excision repair of DNA damage in eukaryotes participates in photoproduct recognition. A search of the current Caenorhabditis elegans database allowed us to identify a good candidate for the XPA protein homolog. We cloned a complete cDNA of C. elegans XPA (Ce-XPA) by using RT-PCR. Northern blot analysis showed that the Ce-xpa gene is expressed in all of the stages, including embryos. Ce-XPA encodes a 241-amino acid protein that is homologous to all known eukaryotic XPA. Ce-XPA RNAi caused embryonic lethality and survival lethality to UV radiation. This result suggests that Ce-XPA is involved in the repair of UV-damaged DNA in C. elegans.