A coronary artery fistula is a direct communication between a coronary artery and one of the cardiac chambers or vessels around the heart. The present study was undertaken to define the incidence, clinical findings and angiographic characteristics of congenital coronary artery fistula in Turkish adults who underwent diagnostic cardiac angiography A consecutive series of 11,350 coronary angiography, performed between January 2000 and December 2001, was retrospectively examined for the presence of coronary artery fistulas. The incidence of congenital coronary artery fistulas was 0.08%. All the patients had chest pain during exertion or at rest. All the fistulas were single and most arose from the proximal left anterior descending coronary artery and drained into the pulmonary artery. All the fistulas were small. Surgical treatment was not indicated. A congenital coronary artery fistula in adults is a distinct though rare entity, variable in its incidence and commonly associated with coronary artery obstructive disease. Diagnosis is mostly incidental during routine coronary angiography.