OBJECTIVE Congenital coronary artery fistulas are frequently identified in adult and pediatric populations and they have been associated with various clinical and morphological features. The purpose of this study was to define the clinical and coronary angiographic morphological characteristics of adult patients with congenital solitary CAFs in the Dutch Registry. RESULTS Fifty-one patients with angiographically documented CAFs were reviewed for clinical evaluation, used non-invasive and invasive diagnostic tools and treatment modalities. Unilateral CAFs were predominant (80%) and 84% of the patients were symptomatic. The most common presenting symptom was angina pectoris (57%). Angina pectoris was present in a quarter of the patients in the absence of coronary artery disease (CAD). Significant CAD was present in 49% of the patients. Twenty-nine percent of the CAFs showed aneurysmal formation, underlying their potential hazard of rupture. Myocardial infarction occurred in 18% of the patients. In 27% of CAFs multiplicity of the origin was found and nearly all fistulas were tortuous (97%). Treatment modalities were conservative medical in 70%, percutaneous transluminal embolisation in 5% and surgical ligation in 25% of the cases. Multiple micro-fistulas from the coronary arteries to the left ventricle were excluded from the study. CONCLUSIONS In this national survey series, congenital solitary CAFs can be presented with typical angina pectoris in the absence of obstructive CAD. Fistula-related coronary artery was infrequently involved in the development of ipsilateral myocardial infarction. Tortuousity and multiplicity of the CAFs may determine, for the individual patient, the choice of the currently available treatment modalities.