The aim of the research – to study the prevalence of vitamin D deficiency in girls and boys – students of the Republic of Bashkortostan. Materials and methods. A study of the reproductive potential of girls and boys aged 15-19 years was carried out. There were 480 girls and 126 boys examined. All students were divided into age subgroups: girls 15-17 years old – 217 people, 18-19 years old – 263; boys 15-17 years old – 76 people, 18-19 years old – 50 surveyed. Blood serum was analyzed for the content of 25(OH)D based on the Roche Cobas 8000 automated modular platform with the e801 immunochemical module. Statistical processing is provided by the Statistica program. Results. This study showed that 62.9% of all surveyed girls have vitamin D deficiency of varying severity, and only 1/3 of the female students had prohormone D levels in their blood plasma at an adequate level and amounted to 37.1% (p1 < 0.0001). If we compare the age group of 15-17 and 18-19-year-old girls with a deficiency of this nutrient, which is 65% and 61.2%, respectively, statistical significance between the subgroups was also revealed (p < 0.05). As for the boys examined, they had vitamin D deficiency of varying severity in 78.6% of cases. And just like in girls, in the younger age subgroup, the deficiency of this nutrient is more pronounced and accounts for 85.5% of the total number (76) of the surveyed boys. Conclusion. To make up for the lack of vitamin D, it is preferable to follow the Mediterranean diet, which includes foods rich in calciferols. At the same time, subsidies for cholecalciferol in the form of drugs or dietary supplements are needed in accordance with the recommendations of the Russian Association of Endocrinologists. In addition, it is proposed to determine the level of 25(OH)D in the blood serum of women planning pregnancy, in order to adjust the dose of vitamin D.