The European Commission asked the Panel on Genetically Modified Organisms of the European Food Safety Authority (EFSA GMO Panel) to update its 2006 scientific opinion on Post-Market Environmental Monitoring (PMEM) of Genetically Modified Plants (GMPs). For doing so, the EFSA GMO Panel made use of the experience gained from its assessment of applications on GMPs for cultivation and considered different sources of information such as the PMEM reports on cultivated GMPs, relevant scientific literature and stakeholders comments. This scientific opinion aims to clarify the objectives, tasks, tools and requirements for PMEM. Firsly, the present document explains the scientific rationale for PMEM, including the concept of developing management and monitoring strategies based on the overall conclusions and assumptions of the Environmental Risk Assessment. Secondly, it provides examples and guidance to applicants on how to develop and implement their plans for Case-Specific Monitoring (CSM), taking into account the case-by-case character of CSM. In addition, it provides guidance to applicants on the strategy, methodology and reporting of General Surveillance (GS). Different tools and approaches to implement a plan for GS are considered. The EFSA GMO Panel proposes a holistic and integrative approach for monitoring GMPs in the EU that considers GS within a framework of general environmental protection monitoring. Finally, the EFSA GMO Panel makes proposals to risk managers for the future conduct of PMEM in the EU and suggests that access to PMEM data could be facilitated by setting-up standardised and centralised reporting centres. This scientific opinion repeals the former 2006 scientific opinion of the EFSA GMO Panel on PMEM of GMPs.