Function of ion transport peptide ITP, also named as crustacean hyperglycemic hormone CHH, is investigated using a Drosophila mutant EP(2)2287 carrying a P-transposable element in the middle of the first intron of itp gene. The putative itp mutant EP(2)2287 is found to be recessive lethal at the late embryonic stage. Surprisingly, doubly heterozygous flies in EP(2)2287 (putative itp mutant) and in eth (ecdysis triggering hormone) null mutant shows deficiency in ecdysis leading to lethality. The ecdysis deficiency phenotype was rescued by injection of either one peptide DrmETH1 or ITP, suggesting the ITP is involved in the cascade actins of neuropeptide controlling insect ecdysis, most likely as a upstream signal of ETH.