The transboundary movement of Genetic Modified Organisms (GMOs) has become a focal point of the international community. The control of GMOs involves huge economic interests and the protection of the environment and public health. In 2003, the World Trade Organization (WTO) at the request of GMOs-producing countries established a Panel in adjudicating the consistency of European nations' restriction on trade of GMO products under WTO rules. Given the high controversy and sensitivity of the dispute, the Panel had conducted a very lengthy deliberation and finally reached a conclusion in September of 2006. This article aims to analyze the legal reasoning of the decision, focusing on how the tribunal interpreted and applied certain critical provisions governing the issue. It is found that this ruling took a rigid stand on the justification of applying trade restriction on GMOs, although the right of WTO members to protect national health has been fairly reaffirmed.