Genetically modified (GM) crops and biotechnology are providing new opportunities for increasing crop productivity and tackling agriculture problems, such as diseases, pests and weeds, abiotic stress and nutritional limitations of staple food crops. As GM crops are being adopted in various locations with different ecosystems, a scientifically based understanding of the environmental effects of cultivations of GM crops would assist decision makers worldwide in ensuring environmental safety and sustainability. In this paper are discussed some of the most important problems related to the GM crops into the environment such as: plant protection, hybridisation, ecological effects of HRCs, gene flow, biodiversity, stress, ecological risks (ERA), effects on the soil ecosystem etc.