With the constant growth of population, the need for food, as well as protein, is increasing. The main source of protein for humans is food of animal origin, and for animals, soybean meal and fish meal. Due to high demand, the prices of protein sources are increasing, and their production leaves a negative effect on our planet. Therefore, there is more and more talk of turning to alternative sources of protein in animal feeding. In a number of studies, insects have proved to be an acceptable substitute for traditional sources of protein because they have a favorable nutritional composition with a high crude protein content and a good amino acid composition, they are easy to grow and process, they reproduce quickly and cause less damage to the environment than farms with domestic animals. This paper discusses the biology, breeding and nutritional values of insects with an emphasis on the black soldier fly (Hermetia illucens) and the mealworm (Tenebriomolitor) as the most promising species, their application in the feeding of certain groups of animals and legal regulations at the level of the European Union.