Traceability and labelling are required by European regulation for food produced from GMOs. For this regulation one of the main advantages of traceability consists in providing information that should allow the precise withdrawal of products from the production process. This paper tests this idea. For that purpose, it seeks to establish whether the mandatory traceability will create an information set refined enough to locate GMO products in the production process. In this respect, the limits of the European regulation are pointed out. It is shown however that results are improved as soon as labelling is introduced alongside the requirement of traceability.