Sex pheromone production in lepidopteran is stimulated and regulated by a pheromone biosynthesis activating neuropeptide (PBAN). A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth (DBM, Plutella xylostella (L.) encodes 338 amino acids. Plx-PBANR has conserved biochemical motifs and 7 transmembranes, indicating it belongs to G-protein coupled receptor family. Plx-PBANR expression was only found in female pheromone gland, demonstrating that pheromone gland is the only molecular target of Plx-PBAN. Human uterus carcinoma (HeLa) was stably transfected with Plx-PBANR gene and its expression was confirmed by RT-PCR analysis. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with Plx-PBAN and Hez-PBAN from Heliothis zea. When RNAi fragment for PBANR was injected into pupae, suppression of PBANR expression was confirmed by RT-PCR and maintained for at least 2 days at post-emergence. Injection of RNA fragment into pupae for inhibition of Plx-PBANR expression also inhibited mating behavior, revealing that reproductive organ of the female has no spermatocyte and that there are no successful reproductive behaviors. These results suggest of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.