In 1996, the first commercial fields of transgenic upland cotton (Gossypium hirsutum L.), expressing the CryIAc insecticidal protein, were grown in the USA (Hardee and Herzog, 1997). The cryIAc transgene was modified after a gene from the bacterium, Bacillus thuringiensis. This genetically engineered cotton, commonly known as 'Bt cotton,' was developed by Monsanto, and Delta & Pine Land Companies as a novel new approach to controlling insect pest injury in production agriculture (Benedict, 1996a; Jenkins, 1999). The commercial production and regulation of Bt cotton technology has been closely followed by the general public, universities, governments, and special interest groups around the world. Genetically transforming cotton and other crops by the addition of foreign genes is viewed by certain public, private and governmental sectors as the most promising new paradigm to reduce pest injury, increase yields and genetically improve crops. However, transforming plants using foreign DNA from non-interbreeding organisms or synthetic DNA artificially produced in the laboratory, has raised questions regarding the impact of these transformed organisms on the environment, health of man, genetic diversity of plant and animal species, and the various religious and philosophical views of mankind. In this chapter we shall review the development and first three years of commercialization of Bt cotton as a novel new insect pest management strategy and tool. We will also discuss the challenges and opportunities in breeding and managing crops genetically engineered to suppress insect injury; and the contributions of these crops to current philosophies of integrated pest management and sustainable agriculture (see Carozzi and Koziel, 1997a; Hall and Menn, 1999 for further discussion on use of transgenic plants and biopesticides in agriculture).