The approval of genetically modified organisms for deliberate release and placing on the market requires environmental risk assessment and environmental monitoring. Methodological approaches and implementation of both tasks are still controversially discussed. This article analyses principles of environmental monitoring of genetically modified organisms as published in the Guideline 4330 Part 1 of the Association of German Engineers. Thereby, the article concentrates on the characterisation of the receiving environment affected by cultivation of genetically modified organisms and the representativeness of monitoring systems to assess large-scale implications of the cultivation of genetically modified organisms. Based on this, the article introduces statistical and geoinformatic measures as well as relevant geodata to deal with these issues.