RNA editing is proposed as a modulator of transcriptomes, but its biological impact has not been fully elucidated. In particular, its importance for transposable elements is controversial. We found RNA editing on antisense read-through transcripts of KP elements, one of the deletion derivatives of P transposable elements in Drosophila melanogaster. Three kinds of RNA editing were detected at 20 sites around the terminal inverted repeats (TIR); 15 A-to-G, four U-to-C, and one C-to-U conversions. A-to-G conversions are suggested to be attributed to A-to-I RNA editing on KP element RNAs, because inosine (I) in RNA is recognized as G by reverse transcriptase. TIRs were deduced to form dsRNAs as a putative target of ADAR. This is the first report of RNA editing on mobile elements of Drosophila.