Anomalous origin of the circumflex coronary artery from the right sinus of Valsalva is the most common coronary anomaly. This anomaly is thought to be of little clinical significance without the presence of severe narrowing of the vessel. A 43-year-old woman was referred to our institution for evaluation of atypical chest pain and equivocal results of the exercise stress test. We decided to perform multislice computed tomography coronary angiography before any other invasive studies. The scan was performed with a 16-row scanner (Aquilion 16 CFX, Toshiba Medical Systems, Tokyo, Japan) after intravenous administration of non-ionic contrast material. Scans revealed that the circumflex coronary artery originated from the right sinus of Valsalva; the initial course was retro-aortic until it reached its target in the atrioventricular groove; peripheral distribution of the circumflex coronary artery was then normal. The anomalous vessel presented a significant stenosis in its proximal tract. Coronary angiography confirmed that the origin of the circumflex coronary artery was from the right aortic sinus and the significant stenosis of the proximal portion of this vessel. This case confirms the full capability and accuracy of multislice computed tomography with the aid of post-processing techniques in the identification and evaluation of the ectopic origin of the left circumflex coronary artery from the right sinus of Valsalva, displaying accurately the origin, size, course, and relationship of the anomalous vessel with respect to surrounding structures.