OBJECTIVES: a: To evaluate the long-term outcome of parapneumonic effusions (PPE) in children regarding lung function and exercise tolerance, (b) to investigate the role of bronchial asthma in the outcome of PPE.METHODS: The design of the study included 51 children with PPE, at least 2 years after the initial infection. They were divided in two groups. Group A (38 children) consisted of children with PPE but without asthma prior initial infection. Group B (13 children) included children with PPE and asthma prior infection. Thirty-six children were taken as healthy controls (group C). All children performed spirometry and a maximal incremental cardiopulmonary exercise test on cycle ergometer.RESULTS: Children of both groups (A and B) showed statistically significant lower values in FVC%, FEV1%, and FEV1 /FVC compared to controls (group C). Children of group B had also significant lower FEF(25-75%) values compared to controls. Children of group B had significant lower FEV1 /FVC values compared to group A. All children of the three groups showed no differences in maximal exercise capacity (VO2max). Children of group A had higher respiratory equivalent to oxygen (VE/VO2) during exercise compared to healthy subjects.CONCLUSIONS: There are small effects on lung function and exercise capacity in the long-term, among children with PPE, but of no clinical importance. Pre-existing bronchial asthma doesn't influence the outcome significantly.