Post-market surveillance (PMS) is increasingly required by some regulatory authorities for the marketing approval of GM-Novel Foods. This requirement, in addition to a complete conventional safety assessment, aims to show that unexpected (adverse) effects do not occur after long-term everyday exposure. Large food manufacturers have systems to obtain feedback from consumers on their products. We show that such systems can be enhanced to collect information on possible health effects of specific products and relate these to intake in specific groups of consumers. The term post-launch monitoring (PLM) is proposed to distinguish the process from that used for pharmaceuticals. GM foods differ from branded products to which existing systems have been applied. The paper discusses whether and how such systems could be applied to GM foods and what additional elements would need to be incorporated in them. A PLM system should define and organize the flow of information between the different stakeholders. We conclude that because such data will be generated from a range of sources and will need to be collated, verified, and integrated, an independent agency will be essential to undertake this activity in order to balance the interests of all stakeholders and ensure public trust.