A cDNA library corresponding to mite protein was screened employing anti-Der f II antibody. Two possible clones were obtained, which contained plasmids, pFL1 and pFL11, respectively. Both plasmids had insertions of about 500 base pairs. The DNA sequences of the two insertions were determined, from which the amino acid sequences were deduced. The amino acid sequence of the purified native Der f II protein could be determined to 45 residues from the N-terminus. As a result of comparison, we concluded that the cDNAs prepared from live mite Dermatophagoides farinae corresponded to the mite allergen, Der f II.