BACKGROUND: Stress testing poses problems in clinical practice in pediatrics: treadmill testing does not permit measuring most physiological parameters during staged-exercise; and pharmacologic testing is non-physiological. Performing echocardiography and Doppler with metabolic measurements during exercise overcomes these limitations. METHODS: Subjects exercised on a semi-recumbent cycle ergometer using a 3-minute step protocol of 20-40 watts at 60-70 rpm until volitional fatigue. Measurements were made at rest, during each stage of exercise, and post-exercise. The protocol was adapted to assess function in patients with special forms of congenital heart disease such as those with univentricular hearts or systemic right ventricles. Testing was not done routinely in children less than 8 years of age. RESULTS: Since 1997 we have performed 660 stress tests on 427 pediatric patients and 28 healthy controls. We have defined a normal response to exercise as an increase in heart rate > 70 bpm, systolic blood pressure > 50 mmHg, a sustained stroke volume index > 20%, a cardiac index double the resting value, an increase in shortening fraction > 10%, MVCFc > 0.2 circ/s, a fall in wall stress, an upward and leftward shift in MVCFc/stress, an increase in contractility of all myocardial segments, and a workload greater than 900 J/kg. CONCLUSIONS: Our stress echocardiography protocol allows us to assess exercise capacity and oxygen consumption, ventricular function, myocardial reserve, segmental wall motion, valvar obstruction, ventricular synchrony, and unmasks systemic and pulmonary venous obstruction.