Background: Perceived correlation between the coronary arterial anatomy in patients with complete transposition, and the outcome of the arterial switch procedure, has made preoperative identification of their patterns standard practice. Purpose: Our purpose was to assess the accuracy of preoperative echocardiographic identification of coronary arterial patterns, to evaluate the necessity of preoperative imaging by angiography, and to determine the impact of the coronary arterial anatomy on outcome. Methods: We reviewed the medical records of all patients referred for an arterial switch operation between August 1995 and January 2000. The anatomy as described at the time of the operation using the Leiden convention was compared to the preoperative echocardiographic and angiographic findings. Results: The procedure had been performed in 67 patients, at a mean age of 9 days, with a range from 3 days to 15 months. In 42 patients, the ventricular septum was intact, while 21 patients had a ventricular septal defect, and the other four had double outlet right ventricle with the aorta anterior and rightward. In 52 patients, the left coronary artery arose from sinus #1, and the right from sinus #2. In 8 patients, the interventricular branch of the left coronary artery arose from sinus #1, with the circumflex coronary artery arising together with the right coronary artery from sinus #2. In three patients, all three coronary arteries arose from sinus #1, while in the remaining individual patients, a large conal branch arose with the left coronary artery from sinus #1, the right coronary and left anterior descending arteries arose from sinus #1, all three coronary arteries took origin from sinus #2, and the left anterior descending and right coronary artery arose from sinus #1 with no circumflex coronary artery identifiable, respectively. In two patients (4%), we identified an intramural coronary arterial course. Echocardiography and angiography were comparable (81% versus 86%) in delineating the coronary arterial anatomy. Patients with a single arterial orifice, or an atypical coronary arterial anatomy, had a slightly longer stay on the intensive care unit, and in the hospital, but showed no difference in mortality. In fact, there was no early mortality (70% confidence limits; 0–2.9%), while two patients died late (2.9%). Conclusion: We conclude that complex coronary arterial anatomy does not preclude a successful arterial switch procedure, although patients with a single coronary artery, or other arterial patterns, had a slightly longer hospital course. Preoperative echocardiographic evaluation is comparable to non-selective coronary angiography. Irrespective of complexity, nonetheless, the coronary arteries can successfully be translocated, obviating the need for preoperative coronary angiography.