Thirteen new patients and 174 patients previously reported with coronary arteriovenous fistula (CAVF) were reviewed to delineate the course and management of CAVF and to clarify the role of surgical ligation in the young asymptomatic patient. Patients were grouped according to age: 99 patients (four new and 95 reported) were less than 20 years old and 88 (nine new and 79 reported) were greater than or equal to 20 years old. Of those under 20 years of age, 19% had preoperative symptoms or CAVF-related complications, including congestive heart failure (CHF) in 6%, subacute bacterial endocarditis in 3% and death in one patient. Seventy-six patients younger than 20 years old had CAVF ligation with only one significant complication. In contrast, 63% of the older group and all of our nine older patients had preoperative symptoms or complications, including CHF in 19%, SBE in 4%, myocardial infarction (MI) in 9%, death in 14% and fistula rupture in one patient. Of the 43 ligated older patients, 23% had surgical complications, including MI in three and death in three. Mean pulmonic-to-systemic flow in the entire group was 1.6:1 and did not differ significantly in those with or without symptoms or complications. One of our patients and one previously reported had spontaneous CAVF closure. In summary, early elective ligation of CAVF is indicated in all patients because of the high incidence of late symptoms and complications and the increased morbidity and mortality associated with ligation in older patients.