The cardiopulmonary performance levels in children who are convalescing from thermal injury are unknown. This investigation was designed to evaluate cardiopulmonary function in children with and without inhalation injury. Forty children with a mean time since burn injury of 2.6 +/- 1.9 years and a mean burn size of 44% +/- 22% total body surface area were selected for the study and divided into two groups: inhalation injury (group 1) and non-inhalation injury (group 2). Pulmonary function studies and cardiopulmonary stress testing were completed on all patients. Both groups reached the same endurance level on the treadmill; however, patients in group 1 did so with an increased expired volume, respiratory rate, and ratio of dead space ventilation to total ventilation which indicated that there were greater demands on the respiratory system. Spirometry and lung volumes at rest showed that 64% of patients in group 1 had abnormal lung function compared with only 27% of patients in group 2.