Objective: To evaluate the use of cardiovascular magnetic resonance (CMR) to visualize angiographically-detected congenital coronary artery fistulas in adults. Methods: CMR techniques were used to study 13 patients, recruited from the Dutch Registry, with previously angiographically diagnosed fistulas. Results: Coronary fistulas were detected in 10 of 13 (77%) patients by CMR and, retrospectively, in two (92%) more. In 93% of these, it was possible to determine the origin and the outflow site of the fistulas. Cardiovascular magnetic resonance allowed demonstration of dilatation of the fistula-related coronary artery in all cases. Tortuosity of fistulas was detected in all visualized patients. Uni-or bilaterality of fistulas as seen on CAG was proven on CMR in all patients. Flow measurement could be performed in 8 patients. A fairly good correlation (r = 0.72) was found between angiographic (mean 6.2 mm, range 1-16) and cardiovascular magnetic resonance (mean 6.3 mm, range 3-15) measured fistulous diameters. Conclusions: Cardiovascular magnetic resonance of congenital fistulas with clinical significant shunting is feasible and can provide additional physiological data complementary to the findings of conventional coronary angiography.