Second and fifth grade schoolchildren living within 19 km from a 1400 megawatt coal fired pcrecer plant are followed up. Their parents filled out an ATS-NHLI health questionnaire and they performed pulmonary function tests (PFT), which included: FVC, FEV1, FEVJFVC, and PEF. T~he effects of socioeconomic background, smoking, habits and pulmonary diseases in the families on the dis~ributi0n of respiratory symptoms, respiratory diseases and PFT of the children were analysed. Higher FEVI/FVC, lower prevalence of respiratory diseases and excess respiratory symptoms were present among children from crowded homes. Mothers' smoking was found to be connected vgith significantly higher prevalence of bronchitis, non significant higher prevalence of asthma, significant lower FEVI/FVC and a trend of lower F E V 1 and PEF among their children. ]louse heating did not effect the prevalence of re. spiratory 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 re~ spiratory 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 t~ose who had pneumonia recently.