This study examines the possible incompatibility between environmental conventions and agreements promoting international trade. More specifically, it aims at discussing the Precautionary Principle and the WTO agreements on trade and how they might contradict each other on the international arena. The study focuses on the international trade with genetically modified organisms and discusses probable needs of reformulating the principles and/or conventions concerned if these are to function as tools of equal importance when handling environmental problems through policy making. The controversy is illustrated through a case-study of a trade dispute where the conflicting principles: the Precautionary Principle and WTO agreements on trade are involved, namely a dispute where a formal complaint to the WTO by the US, Canada and Argentina about the European Community supposedly applying a de facto moratorium on genetically modified organisms had the final outcome of the European Community being found to contravene international trade rules. The study concludes that actors on the international arena are still opinions apart concerning the way to perceive possible risks connected to biotechnology and genetically modified organisms. This incongruence is also found to apply to the status of the Precautionary Principle as a rule of international law as well as to which of the conventions that were applicable to the concerned dispute.