Europe has probably the strictest GMO regulation in the world.  Its objectives are to give maximum protection of public health and the environment, while at the same time providing a science-based regulatory structure where biotechnology can flourish.  In contrast to the situation in the USA, European opinion on the health and environmental biosafety of GMOs has been highly polarized, with the result that the public has expressed the desire of having an informed choice in what they are eating.  Consequently, the European Union has introduced legislation on the traceability and detection of GMOs, including labelling of food and feed containing GMOs, or derived products thereof, above a defined threshold of fortuitous presence.  This review article summarizes EC regulations, directives and recommendations on traceability and labelling, and discusses the practical problems involved in their implementation.  These include the definition of the labelling threshold and the units of measure, sampling of large cargos, mixtures of GMOs, stacked genes, unauthorized GMOs, unknown GMOs and asynchronous approval.  The ways in which the EC integrated project Co-Extra is contributing to the resolution of these problems are also discussed.