Abstract: It is intended to identify or estimate miRNAs and one or more target genes (target mRNAs) targeted thereby. A method of predicting or identifying miRNAs and one or more target mRNAs targeted thereby, which comprises calculating the most stable secondary structures of double-stranded RNAs, which can be formed by all partial sequences in all of the subject mRNAs with miRNAs, and the secondary structure energies thereof to thereby search for all partial sequences capable of having stable structures through the binding of miRNAs to mRNAs, and then calculating the most stable secondary structure, which can be formed by a subject partial sequence or regions in the vicinity of the subject partial sequence with partial sequences of the concerned mRNA, and the secondary structure energy thereof to thereby determine whether or not the subject partial sequence of the concerned mRNA has a structure capable of interacting with the miRNA.