The ability to genetically engineer insects other than Drosophila melanogaster has further extended modern genetic techniques into important insect pest species ranging from fruit fly pests of horticulture to mosquito vectors of human disease. In only a relatively short period of time, a range of transgenes have been inserted into more than 10 insect pest species. Genetic transformation of these pest species has proven to be a very important laboratory tool in analyzing gene function and effects on phenotype however the full extension of this technology into the field is yet to be realized. Here we briefly review the development of transgenic technology in pest insect species and discuss the challenges that remain in this applied area of insect genetics and entomology.