In this paper, the issue of regulation of and trade in genetically modified organisms (GMOs) is examined. It is shown that, despite rapid adoption of GMOs by a few exporters, many importers have developed relatively restrictive procedures for premarket approval of GMOs, and are requiring mandatory labelling. Although exporters have yet to seek a ruling on these regulations, a trade dispute over GMOs is likely to occur. An analysis of the reasons for such a dispute is presented in the paper, along with a discussion of whether such a dispute can be resolved through existing World Trade Organization procedures.