Aims: Our purpose was to assess the value of magnetic resonance angiography as a non-invasive alternative to catheterization in the evaluation of patients with tetralogy of Fallot, including those with pulmonary atresia. Methods and results: We evaluated prospectively, using magnetic resonance angiography, 30 patients, aged from 1 to 18 years, 15 with tetralogy of Fallot and pulmonary stenosis, and 15 with pulmonary atresia. The studies obtained using magnetic resonance provided adequate visualization of the aorta, and provided excellent imaging of the pulmonary trunk and its right and left branches. Compared with catheterization, magnetic resonance had 100 percent sensitivity, specificity and accuracy for defining the presence or absence of the pulmonary arteries. Magnetic resonance also had 93.9 percent sensitivity, 98.2 percent specificity, and 96.7 percent accuracy for detection of stenosis or hypoplasia of the pulmonary arteries. We detected 25 major aortopulmonary collateral arteries with magnetic resonance, but only 22 with conventional angiography. There was complete agreement between the two methods in detecting patency of the arterial duct in 6 patients, and of Blalock-Taussig shunts in 12 patients. Conclusion: Magnetic resonance angiography is a useful tool in the evaluation of patients with tetralogy of Fallot. It can be considered a non-invasive alternative to cardiac catheterization in the evaluation of the pulmonary vascular anatomy.