House dust mites produce antibacterial proteins suppressing bacterial growth. The 14.5-kDa bacteriolytic protein (UniProtKB Q8MWR6) has been known in Dermatophagoides pteronyssinu. Trouessart. We have applied polymerase chain reaction and reverse transcription-PCR to detect a homologous gene sequence coding for a Q8MWR6-related protein in Dermatophagoides farina. (Hughes) using genomic DNA and total RNA, respectively. The resulting PCR product of expected size, 243 bp, was obtained from both Dermatophagoide. spp., while no amplification was achieved from stored product mite samples. Sequence of the gene fragment from D. farina. showed 83% similarity to the previously described one in D. pteronyssinu.. Successful amplification of the expected product from cDNA generated with oligo-dT primer implies that the NlpC/P60-like protein in Dermatophagoide. mites is of eukaryotic or mite origin.