The authors investigated the relationship between household environmental tobacco smoke (ETS) exposure and prevalence of respiratory symptoms and diseases as well as absenteeism related to respiratory illness in schoolchildren. The study sample consisted of 1,074 children aged 7-11 years from three primary schools in Nis (Serbia). ETS exposure was associated with wheezing (OR-1.48; 1.09-2.01), bronchitis (OR-1.66; 1.23-2.23), headache (OR-1.45; 1.08-1.95), and fatigue (OR-1.38; 1.02-1.85) in exposed children. The other risk factors with possible influences weren't assessed. There was no statistically significant difference in the number of physicians' visits as well as in absenteeism from school due to illness in children exposed to ETS in comparison to non exposed children. The tobacco smoke effect on children is an essential and urgent problem with life lasting negative health effects which are preventable.