Exercise testing in children is performed for evaluation of maximal work capacity and adds important data for the formulation of an exercise prescription. Indications for testing are (1) assessment of oxygen supply/demand ratio in congenital heart defects, (2) evaluation of chest pain, (3) evaluation of dysrhythmias, (4) evaluation of systemic hypertension by blood pressure response to exercise, (5) evaluation of the results of medical and/or surgical therapy, and (6) the evaluation of the respiratory component of the disease. The methods of testing are described.There are very few contraindications to exercise in children with heart disease. Most of these children can exercise without restriction. Children with symptomatic heart disease should have their exercise modified based on clinical evaluations and exercise testing. Except for acute inflammatory disease or profound congestive heart failure, children with heart disease should be given a progressive exercise program to predetermined level. They should he retested after six months in the program to modify the levels of exercise. The details of physical rehabilitation programs for children with heart disease are discussed.