Although some patients with fulminant myocarditis can be rescued owing to the improvements in mechanical circulatory support therapy, there are few reports providing evidence of cardiac rehabilitation during mechanical circulatory supports, particularly among pediatric patients. We treated two pediatric patients who underwent aggressive cardiac rehabilitation during mechanical support. Five days after the initiation of extracorporeal membrane oxygenation therapy aggressive cardiac rehabilitation was started in a 10-year-old girl with fulminant myocarditis. After explantation of the device, she was discharged on postoperative day 23. A 6-year-old girl with fulminant myocarditis started receiving cardiac rehabilitation two days after the initiation of an extracorporeal left ventricular assist device, despite having hemiplegia due to a recent broad stroke. She achieved an exercise capacity of supported walking for 280 meters after 127 days of cardiac rehabilitation and then went abroad to undergo heart transplantation when she was in the best physical condition possible. Early initiation of cardiac rehabilitation may be safe and effective for successful pediatric mechanical circulatory support therapy; this acts as a bridge to explantation or heart transplantation.(Int Heart J 2016; 57: 769-772)