Second and fifth grade schoolchildren living within 19 km from a 1400 megawatt coal fired power plant are followed up. Their parents filled out an ATS-NHLI health questionnaire and they performed pulmonary function tests (PFT), which included: FVC, FEV1, FEV1/FVC, and PEF. The effects of socioeconomic background, smoking habits and pulmonary diseases in the families on the distribution of respiratory symptoms, respiratory diseases and PFT of the children were analysed. Higher FEV1/FVC, lower prevalence of respiratory diseases and excess respiratory symptoms were present among children from crowded homes. Mothers' smoking was found to be connected with significantly higher prevalence of bronchitis, non significant higher prevalence of asthma, significant lower FEV1/FVC and a trend of lower FEV1 and PEF among their children. House heating did not effect the prevalence of respiratory symptoms and diseases of the children. Significantly higher prevalence of respiratory symptoms and diseases was found among children, whose families reported about a history of pulmonary diseases, but no reduction of PFT parameters could be found among them. Mothers' contribution to respiratory symptoms and diseases of their children seems to be more significant than that of the children's fathers. Most respiratory symptoms were more common among children with a history of pneumonia in childhood, especially those who had pneumonia recently.