An issue related to insufficient provision with vitamins among children in Russia requires profound examination, especially as regards reasons for it, as it will allow to work out targeted prevention measures. Our research goal was to perform hygienic assessment of environmental factors (organization of nutrition, chemical contamination of environmental objects) that influence provision of pre-school children with vitamins. We chose the following research objects: a typical pre-school children facility located in a large industrial center and 188 children aged 6–7 who attended it. We applied a set of sanitary-hygienic, laboratory, and mathematical techniques in our research. We assessed organization of nutrition in the facility; performed a comparative analysis of nutrition quality with calculation and individual weighting technique. We also examined concentrations of technogenic chemicals in the atmospheric air, the air inside the facility, and water supplied to the facility; determined their concentrations in children's blood; studied antioxidant protection system in children and a level of their provision with vitamins. We detected that nutrition in the facility was imbalanced, and actual consumption of some food products was up to 1.7 times lower that it was suggested in a menu, and actual introduction of vitamins was by 30 % lower than calculated one. We showed that environmental objects (the atmospheric air, indoor air, and drinking water supplied to the facility) on industrially developed territories were contaminated with technogenic chemicals (formaldehyde, phenol, ethylbenzene, chloroform, and residual free/fixed chlorine) and it led to occurrence of their increased concentrations and increased concentrations of their metabolites in children's blood. We proved that increased concentrations of oxygen-containing aldehydes, aromatic hydrocarbons, and chlorine-organic compounds in children's blood made antioxidant protection enzymes less active and caused lower concentrations of antioxidant-active vitamins. So, insufficient provision with vitamins among pre-school children who attend a pre-school children facility in a large industrial center is caused not only by insufficient exogenous introduction of vitamins with food but also by effects of their metabolic absorption related to occurrence of technogenic chemicals with pro-oxidant effects in biological media.