The article examines the main reasons for the increase in chronic diseases and deterioration of children's health in modern conditions. Factors of an ecological, medical, economic, and behavioral nature, as well as their interrelationship and complex impact on the child's health, are analyzed. Special attention is paid to the importance of early prevention, which should begin even before birth and continue in childhood. As a measure, a systematic approach is proposed, including improving the environmental situation, increasing access to medical care, supporting socially vulnerable families, and promoting a healthy lifestyle. A table structuring the causes and preventive measures is presented. The article is intended for specialists in pediatrics, public health, as well as a wide range of readers interested in children's health issues.