Objective: To analyze the concentrations of vitamin D in the blood serum in children. Materials and methods:Retrospective analysis of vitamin D (25-hydroxycholecalciferol) levels in the blood serum of 2008 children.Results: 41.2% (828) of tests were performed in children under 2 years of age and 58.8% (1180)-for children over 2 years of age. Vitamin D concentrations significantly differ between the groups: 52.1% of children younger than 2 years had an increased concentration of vitamin D and 19.0% had vitamin D deficiency, while the majority (74.0%) of children older than 2 years had the vitamin D deficiency. Conclusions:The intake of vitamin D is not optimal among the children in Lithuania. More than a half of children younger than 2 years receive too high doses of vitamin D, whereas 74% of older children suffer from constant vitamin D deficiency.