The main goal of the study was to check the hypothesis that pertussis infection may cause a lung function deterioration in children. Cross sectional study was carried out in 1997 among 992 schoolchildren attending the fourth form of elementary schools in Krakow. In the course of the study the epidemiologic interviews on respiratory health of children and spirometric testing were performed. Spirometric indices (FVC, FEV1 and FEF25-75%) were inversely correlated with allergic diseases, wheezing symptoms and tobacco smoking of mother in pregnancy, however, the effect of the latter variable was of border significance. Socio-economic status of the family and number of infections in lower respiratory tract in children reported over the last year were not related to the lung function level. Children who reported pertussis infection in the past showed significantly lower values of FEV1 and FEF25-75%. The results obtained suggest that pertussis infection may have a detrimental effect on the lung function of preadolescent children. Since these children may be more susceptible to environmental hazards and development of obstructive lung disease, therefore, it is justified to postulate a monitoring of lung function in children after pertussis infection throughout a longer period to detect early lung obstruction and setting up proper prophylactic measures.