PURPOSE: To prospectively evaluate the feasibility of magnetic resonance (MR) coronary artery imaging and to define myocardial damage with late-enhancement myocardial MR imaging in children who underwent arterial switch surgery for transposition of the great arteries. MATERIALS AND METHODS: The local research ethics committee approved this study, and the subjects and/or a parent or guardian gave informed consent. Sixteen asymptomatic subjects who had undergone arterial switch surgery for transposition of the great arteries were studied (mean age, 10.8 years +/- 1.3; 11 male subjects, five female subjects). MR coronary angiography, late-enhancement MR imaging, global ventricular function, and regional wall motion were assessed. Fifteen children were awake during imaging; one was imaged with the use of general anesthetic. RESULTS: In 23 (72%) of 32 coronary arteries imaged, diagnostic-quality images of the coronary ostium and proximal coronary artery course were acquired; this increased to 100% in subjects older than 11 years. No coronary ostial stenoses were seen. In all subjects, the proximal course of the coronary arteries was visualized. Two subendocardial viability defects were detected, which corresponded to known compromise of the artery that supplied that territory at the time of surgery. Global left and right ventricular function were preserved, with no regional wall abnormalities. CONCLUSION: Diagnostic-quality MR coronary angiography is feasible in subjects who have undergone arterial switch surgery for transposition of the great arteries, with no unexpected areas of myocardial infarction detected.