Transgenic cottons expressing the crystal protein toxin genes from the bacterium, Bacillus thuringiensis (Bt) have progressed to the field testing stage and may soon become part of the Australian cotton production scene. Bt cottons offer the potential for highly efficacious use of the Bt proteins and for significant reductions in the requirement for pesticides to control Lepidopterous pests like Helicoverpa. These reductions should reduce environmental concerns associated with cotton growing, and from the viewpoint of IPM will allow the implementation of other novel management strategies which are not compatible with pesticide use (eg. food sprays, pheromones, various parasites and predators). In future these other methods may help in management of pests other than Helicoverpa. Bt cottons are thus compatible with many other IPM tools and will provide a new platform on which IPM systems can be based