In this study, we sought to assess the cardiopulmonary functions in three pediatric heart transplant recipients, two of whom are with dilated cardiomyopathy, whereas one is with cyanotic heart disease, in early postoperative period. Cardiopulmonary exercise testing was performed using an incremental cycling at 1 mo after surgery. The results revealed that our study subjects had obvious impairment in workload, oxygen consumption, and oxygen pulse at peak exercise and ventilatory threshold at 1 mo after orthotropic heart transplantation. The pediatric orthotropic heart transplantation recipients also showed a high resting heart rate (90-106 beats/min), a low peak heart rate (109-117 beats/min) during exercise, and continuous heart rate acceleration till 1 to 3 mins after the cessation of exercise. In conclusion, pediatric orthotropic heart transplant recipients have a low cardiopulmonary endurance during the early postoperative period. An early structured, individualized cardiopulmonary rehabilitation program for pediatric orthotropic heart transplant recipients will be an area for future evaluation and research.