The optimal management of paediatric empyema thoracis remains controversial. The objective of the study was to analyse evolving experience in clinical presentation, management, outcome and factors contributing to adverse morbidity in thoracic empyema. Forty-seven patients presenting to a paediatric surgical centre were studied in three consecutive 6-y periods during 1980-97 to compare any change in the pattern of disease influencing diagnosis and management. Patients were categorized into two treatment groups: (i) conservative management (antibiotics and/or tube thoracostomy), (ii) thoracotomy. The median duration of illness prior to hospital admission was 10 d (range 1-42 d). Ultrasound was increasingly utilized in the diagnosis and staging of empyema and played an important role in directing definitive management. The presence of loculated pleural fluid determined the need for thoracotomy. Sixteen of 20 patients (80%) who were initially treated with thoracocentesis or tube thoracostomy eventually needed thoracotomy. There was a positive shift in management towards early thoracotomy resulting in prompt symptomatic recovery. Significant complications were noted in seven children who had delayed thoracotomy. These included recurrent empyema with lung abscess (n = 2), scoliosis (n = 2), restrictive lung disease (n = 1), bronchopleural fistula (n = 1) and sympathetic pericardial effusion (n = 1). An unfavourable experience with delayed thoracotomy during the study period has led us to adopt a more aggressive early operative approach to empyema thoracis. The decision to undertake thoracotomy has been influenced by the ultrasound findings of organized loculated pleural fluid. Delayed surgery was associated with adverse outcome. Whilst fibrinolytics and thoracoscopy may provide attractive options for early empyema, thoracotomy can hasten patient recovery regardless of the stage of disease. Prospective randomized trials are required to assess the ideal therapy for childhood empyema.