Anomalous coronary arteries are rare. Although most are not clinically significant, the most clinically important coronary anomaly is origin of the left main coronary artery from the right sinus of Valsalva, which can be associated with sudden death. We present a case of a 37-year-old man with unstable angina who underwent cardiac catheterization and was found to have this type of anomaly, which was later confirmed by coronary computed tomography angiography. Diagnosis and management of patients with this coronary anomaly are discussed.