Spirometry was performed and response to exercise was measured in 15 children following recovery from empyema to evaluate the impact of pleural infection on subsequent lung function. Seven children underwent chest tube drainage; eight did not. The two groups were similar in age (mean +/- SD, 6 +/- 5 years), sex distribution, bacterial pathogen-producing empyema, and age at follow-up evaluation (12 +/- 5 years). Only one child reported recurrent respiratory symptoms. No child had restrictive spirometric changes (total lung capacity, less than 80%; vital capacity, less than 80% predicted) but seven of 15 had a reduced forced expiratory volume in 1 second (less than 80% predicted) or forced expiratory flow during the middle half of the vital capacity (less than 75% predicted), suggesting mild airway obstruction. No child demonstrated reduced exercise tolerance due to restrictive ventilatory limitations. Mild obstructive abnormalities in lung function were identified with equal frequency in children treated with and without chest tube drainage.