GM plants are widely grown all over the world, but many constraints still tend to discourage their use in Europe. Potential risks suggested to be associated with the use of GM are unexpected gene effects, allergenic potential, antibiotic resistance, gene flow. GM feed safety is presently evaluated by adopting the concept of GM substantial equivalence, by comparison with non-GM isogenic crops. Comparison is based on a wide spectrum of chemical components and on livestock performance. From the available experimental data, currently utilized GM plants appear safe and show no effects on animals or animal products. Hence, although they potentially exist, safety risks caused by the use of GM plants appear to be so low as be negligible in comparison with their potential benefits, if appropriately designed. GM plants represent a valuable option for future breeding, to increase yield while reducing the use of pesticides, improve plant adaptation to unfavourable environments, and produce better quality crops, also from a nutritional point of view. Nonetheless, GM crops are novel foods and the assessment of their safety using a scientific sound approach seems essential to protect the environment, as well as the health of humans and livestock.