While GTAP has been used extensively to analyse national and global impacts of trade and other policies, it has been exploited much less for understanding the much larger (in proportional terms) distributive outcomes within countries of such shocks, or of shocks that have a feedback effect on trade policies. Yet we know that redistributive effects are at the heart of trade and other regulatory policy formation. This paper uses GTAP to examine how the adoption of new agricultural biotechnologies affects the welfare of key groups within both adopting and nonadopting countries (a) in the absence of trade or other policy responses and (b) in their presence. This adds to our understanding as to why countries have adopted such widely differing policies towards GMOs.