Aim: To establish reference intervals for chemical elements in hair samples of children and adolescents living in the Western region of Kazakhstan.Material and Methods: This cross-sectional study was conducted in the Western region of Kazakhstan, including the Aktobe, Mangistau, West Kazakhstan, and Atyrau regions. A total of 2,279 healthy children and adolescents (1,099 boys and 1,180 girls) aged 5 to