AbstractThis paper draws on three studies that use existing empirical models of the global economy to examine what the effects of some (non-European) countries adopting genetically modified organisms (GMOs) might be without and then with some policy or consumer preference responses. Specifically, the effects of an assumed degree of GMO-induced productivity growth in selected countries are explored for cotton, rice, and maize plus soyabean. In the maize/soyabean case, the results are compared with what they would be if: Western Europe chose to ban consumption and hence imports of those products from countries adopting GM technology; or some Western European consumers responded by boycotting imported GM foods. Four conclusions emerged from the analyses. First, the potential economic welfare gains from adopting GMO technology in even just a subset of producing countries for these crops is non-trivial. Second, an import ban on GM crops by Western Europe would be very costly in terms of economic welfare for the region itself. Third, even if many consumers in Western Europe are concerned about GMOs, letting consumers express that preference through the market reduces the welfare gains from the new technology much less than if a ban on GMOs is imposed in Europe. Fourth, large though the estimated welfare gains from adoption of GM technology are, they are dwarfed by the welfare gains that could result from liberalizing global markets for farm products and textiles and clothing.