On the basis of field tests and laboratory analyses we have determined the influence of different forms of mineral fertilizers on the microelements content of long-fibred flax during all its vegetation. Thus, non-root additional fertilization of flax by microfertilizers is a quick-acting highly-efficient method of regulating plants microelements content with the aim of creating optimal conditions for their growth and development at the early stages of life, as well as controlling phyto-pathological situation on the flax field. The obtained facts about regularities of microelements getting into plants of long-fibred flax have not only theoretical but also practical importance. They can be the basis for the development of rational system of microfertilizers application for this crop.