Technical Abstract: The adoption of transgenic crops producing insecticidal proteins of Bacillus thuringiensis (Bt) continues to expand rapidly worldwide. This rapid expansion has prompted extensive debate over multiple issues related to human safety and environmental risk. The U.S. Environmental Protection Agency (EPA) requires toxicological testing of a limited number of non-target organisms as one component of the registration process. However, there have been calls by research advisory and private advocacy groups for long-term field studies to examine ecological impacts of transgenic crops as a key component of post-commercialization testing. Chief among these is the impact of transgenic crops on non-target organisms and biodiversity. In response to the rapidly growing importance and interest in transgenic technologies as new tools for modern pest management, this issue of Environmental Entomology introduces a new research section entitled “Transgenic Plants and Insects”. To inaugurate this new section, we have gathered together 13 field studies from across the U.S and Australia that focus on the longer-term assessment of potential non-target effects of cotton and corn producing insecticidal proteins of B. thuringiensis with activity against lepidopteran and coleopteran pests. Collectively, this group of studies lends strong support to the conclusion that Bt cotton and corn pose a relatively low risk to non-target arthropods, and it serves to improve and refine future research questions addressing non-target impacts.