A cDNA clone encoding the ADP/ATP translocase in Helicoverpa armigera has been identified by RT-PCR, 5′and 3′RACE methods. Sequence analysis shows that it is 1 190 bp long and contains a single open reading frame (ORF, 133~1 033 bp) encoding a protein of 300 amino acids (GenBank submission number, AY253868). The protein has a 22 aa signal peptide on its N-terminal, which leads the protein locating onto the inner membrane of the mitochondria. It also has three conserved domains of the mitochondrial carrier protein forming a channel to exchange ATP and ADP energy molecule through the inner membrane of the mitochondria. It shows extensive similarities to the known ADP/ATP translocase poly-peptides. The ADP/ATP translocase similarity was up to 90% in the Lepidoptera.