Vitamins are a group of biologically highly active, low molecular weight organic compounds of various chemical nature, which are practically not synthesized in the human body or are synthesized in insufficient quantities, mainly income with food, and are vital to ensure for the flow and regulation of metabolic processes in the body. Vitamins are micronutrients that are among the essential (essential) factors of nutrition, their content in food is small, usually in the range from 10 to 100 mg/100 g. Vitamins have an exceptional property — the ability to high biological activity in small doses, without being a source of energy or plastic material, act as biological catalysts for vital body functions. According to physicochemical properties and solubility, vitamins A, E, D belong to fat-soluble, are characterized by thermal stability, resistant to cysts and alkalis, their main characteristic is the ability to promote the assimilation of mаcro- and microelements. Vitamins A, E, D are needed at all stages of growth and development of the child's body, the processes of adaptation. The main types of vitamins metabolism disorders are vitamin deficiency, hypo-, hyper- and dysvitaminosis, polyvitaminosis. It is important to constantly monitor the sufficient content of each vitamins in the daily diet of children. The following methods of assessing vitamin supply are known: clinical, biochemical, calculation of vitamin content. Purpose — to increase knowledgment about the effects of vitamins A, E, D, their importance in metabolism, to analyze the main types of their metabolism disorders, to present possible methods for assessing the supply of vitamins in children. Conclusions. The child's body needs a constant supply of vitamins to maintain their amount at the required level. All vital processes take place in the body during the direct participation of vitamins. Future research in the field of the vitamins A, E, D effects will contribute to a better understanding of their role in ensuring the optimal functioning in a human body. Screening and elimination of vitamin A, E, D deficiency in children can not only improve health, but also help increase the life quality. No conflict of interest was declared by the authors. Key words: vitamins A, E, D, vitamin deficiency, hypovitaminosis, hypervitaminosis, dysvitaminosis, polyvitaminosis, children.