The article presents some information on environmental conditions of a single of the largest in the North-West Federal District. Have learned the basic indicators of the health of children living in St. Petersburg, testifying of irregularities in the health of children. Negative tendencies in the dynamics of the basic of Medical and Biological health parameters studied group. In order to enhance the prevention occurrence of diseases are outlined organizational measures directed at strengthening the health of children living in the modern ecological situation of a large industrial center of the Russian Federation.