Some patients with congenital cardiac anomalies develop their first symptoms as adults, and many more will survive to adulthood with congenital lesions that have been treated surgically. Magnetic resonance imaging (MRI) currently provides sufficient morphological information to allow the anatomical diagnosis of congenital abnormalities involving the heart and the great arteries. Newer MR techniques have also been developed that provide functional information such as measurements of valve gradients, stroke volumes, regurgitant volumes, and shunt volumes. Cardiac evaluation utilizing MR techniques may soon replace cardiac catheterization for the preoperative diagnosis of congenital heart disease and its long-term follow-up.