The number of insect neuropeptides identified chemically grows rapidly and many important neuropeptides have already been characterized. After multi-year efforts, diapause hormone and pheromone biosynthesis activating neuropeptide have recently been isolated and sequenced, respectively. New approaches to search for new insect neuropeptides have been carried out by some groups of workers, which have succeeded in identifying several unique peptides. Cloning of cDNA or genomic DNA for insect neuropeptides showed new information about structure and function. It was found that two functionally distinct neuropeptides, Bombyx diapause hormone and pheromone biosynthesis activating neuropeptide, are encoded in a single gene.