The SINPHONIE project was the first Europe-wide project to monitor the school environment and children's health in parallel in 23 European countries. SINPHONIE assessed the air quality (indoor and outdoor) and associated children's health in schools throughout Europe using common and standardized methodologies and tools. As part of the extensive SINPHONIE data base obtained on children in Serbia here we present the correlation between the exposure to tobacco smoke –ETS (household smoking or maternal smoking during pregnancy), birth weight and lung function in children living in rural and city areas.Method: Data were obtained from 300 children (rural and urban group) and their parents using adapted questionnaires' (birth weight, ETS exposure) and spirometry testing performed by all children (FEV1, FVC and FEF 25-75).Results: Statistical method used was Spearman correlation test. It showed weak negative correlation between ETS and decline of FVC.(r=-0.17 p=0.077. ) and FEV1( r=-0.20 p=0.037), both in children from rural areas. Weak negative correlation between maternal smoking and lower birth weight in children from city areas was obtained.( r=-0.20 p=0.026) Conclusion: childhood exposure to environmental tobacco smoke (ETS) adversely affects lung function. Exposure to maternal smoking during pregnancy is associated with low birth weight and lower values of FEV1 and FVC.