Objectives: We sought to determine anatomic features associated with evidence of myocardial ischemia and sudden cardiac events (arrest or death) for patients with anomalous aortic origin of a coronary artery. Methods: We enrolled 560 patients, less than or equal to 30 years, at diagnosis from 40 institutions. Ischemia was defined as the presence of exertional syncope, a sudden cardiac event (arrest/death), or abnormal investigation results. Data on detailed anatomic features were abstracted from echocardiography, computed tomography, magnetic resonance imaging, operative, and/or surgeon-completed reports. Results: There were 236 patients with negative ischemia test results, and 49 with evidence of ischemia (including 18 who presented with a sudden cardiac event); 275 asymptomatic patients who had not undergone provocative ischemia testing were excluded from primary analyses. Patients with ischemia (vs without), were more likely to have left anomalous coronary arteries (28/49 vs 46/236; P <.0001). Of patients with ischemia (vs without), those with anomalous left coronary arteries were more likely to have an intramural coronary artery course, or a high or slit-like coronary artery orifice. Of patients with ischemia (vs without), those with anomalous right coronary arteries were more likely to have a longer intramural course. Among patients with ischemia, the occurrence of sudden cardiac events was not shown to have any associated anatomic features. Conclusions: Anatomic features including coronary artery involved, intramural course and length, and orifice anomalies were associated with evidence of myocardial ischemia for patients with anomalous aortic origin of a coronary artery. These features might importantly inform risk stratification and decisions regarding surgical management.