Transgenic crops expressing one or more Becillus thuringiensis Berliner (Bt) toxins are being commercialized worldwide, primarily because of their efficacy against several economically-important lepidopteran pests. However, the risk of insects developing resistance to Bt toxins concerns organic growers, farmers, and seed producers. Because of the ecology and migratory ability of several lepidopteran pests, the USA and Mexico share geographical overlap with cropping systems that include Bt maize, Zee meys L.; and Bt cotton, Gossypium hirsutum L.; that impact these pest species. With mobile pests and concern for the development of proactive resistance management programs, scientists from both countries have organized meetings and workshops since 2003. This manuscript summarizes the achievements of the USA and Mexico collaborations in surveying Bt-expressing crops and pest dynamics from 2003 to 2010.