Advances in heart surgery over the past 30 years have significantly improved the prognosis of congenital heart diseases (CHD). Therefore, the epidemiology of CHD has changed dramatically with a shift of mortality from pediatrics to adulthood and an increased prevalence of complex CHD. Today, caregivers and patients focus their interests to new perspectives: improving the quality of life, practicing sports, improving psychosocial care. Cardiac rehabilitation is completely integrated in these new therapeutic strategies. The starting point is the cardiopulmonary exercise test (CPET), with the measurement of oxygen uptake, or "VO2". CPET is now recommended in the follow-up of the adults with CHD. Maximum oxygen uptake correlates to the quality of life of children and adults with CHD. The principles of the rehabilitation in patients with heart failure may usually be applied to CHD patients. Some studies in complex CHD showed improvement of VO2 and quality of life after rehabilitation, without any adverse events. However few physicians have the experience in rehabilitation among CHD patients, especially children. Randomized trials on cardiac rehabilitation in adult and pediatric CHD patients are essential to increase the level of evidence and lead to specific guidelines in this population.