Air pollution is the most important environmental health risk leading to premature mortality, respiratory and other health problems. The aim of this study was to quantify its impact on infants and children in Warsaw (Poland), following the principles of Health Impact Assessment method. Particulate matter (PM(2.5) and PM(10)) was considered as the indicator of air pollution. Exposure-response functions between air pollution and health impacts were employed based on the literature. According to the calculations, around 5,201 asthma symptoms and 234 hospital respiratory admissions were caused annually due to air pollution. Hospitalizations due to cardiovascular problems related to air pollution amounted to 13. The mortality among infants and children is relatively low and occurs mostly in the postneonatal period. Nonetheless, approx. 5 mortality cases were assessed to be air pollution-attributable. The study demonstrates a significant impact of air pollution on infants and children, which is manifested primarily as a range of respiratory problems.