Between 1962 and 1980, 50 children admitted to Strong Memorial Hospital had a pleural effusion or an empyema associated with pneumonia. Such parapneumonic effusion and empyema accounted for 52 per cent of cases of pleural effusion and empyema of all etiologies admitted during those years. Review of cases of parapneumonic effusion and empyema suggested that clinical manifestations, laboratory, and roentgenographic findings did not separate these two groups of patients before thoracentesis was performed. Specific organisms were identified in 29 per cent of cases with parapneumonic effusion and 62 per cent with parapneumonic empyema. Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes were responsible for 35, 30, and 20 per cent of cases, respectively. Parapneumonic effusions were treated without closed-chest tube drainage in 76 per cent of the cases, while closed-chest drainage was necessary in virtually all cases of children with empyema.