The presented empirical study assesses the state of the cardiovascular system of Moscow schoolchildren living in different environmental conditions. 233 practically healthy schoolchildren (109 boys and 124 girls aged 11.4 to 12.6 years) took part in the comprehensive study of HRV and the state of adaptive processes when living in different ecological conditions of the capital megapolis. On the basis of different ecological and social conditions the schoolchildren were divided into 4 compared groups. The comparative analysis of the obtained HRV data of schoolchildren of different groups showed differences in the adaptation processes and in the indices of the wave activity of the sympathetic and parasympathetic departments of the ANS.