The 4th Pacific Rim Conference on the Biotechnology of Bacillus thuringiensis and Its Environmental Impact was held in the Manning Clark Centre, Australian National University, from 11''' to 15'" November 2001. The conference attracted 111 registrants from 17 countries, 49 of whom were from Australia. In the seven symposia of the program, 26 invited speakers reviewed major issues for the use of Bt technology (public perceptions, safety, regulatory issues, environmental impact of Bt crops, mode of action of Bt toxins, resistance, and novel Bt toxins). There were also 19 contributed papers and 18 posters presented. The conference was supported by sponsorship from 11 corporations and government agencies.