OBJECTIVE Coronary angiography is the gold standard for imaging the coronary tree, but the relation of coronary artery fistulas to other structures, and their origin and course, may not be apparent. We evaluated the ability of multiplane color Doppler transesophageal echocardiography to identify coronary fistulas. METHODS Twenty-one patients with angiographically confirmed coronary artery fistulas were investigated by transesophageal echocardiography in four Italian hospitals between January 1997 and May 2001. RESULTS Transesophageal echocardiography correctly diagnosed fistulous connection in all 21 patients. This included 6 patients with connections from the left circumflex artery (into the right chambers of the heart in 5 patients, and into the left ventricle in 1 patient), 10 patients with a fistula arising from the left anterior descending artery or left main coronary artery (with drainage into the right ventricle or main pulmonary artery), and 5 patients with a fistula from the right coronary artery (with drainage sites in the lateral aspect of the right ventricle, the low posterior right atrium, or the superior vena cava). In 4 of the 21 patients, angiography did not identify the precise site of a fistula into the coronary sinus or right ventricle. CONCLUSIONS Color Doppler transesophageal echocardiography is useful in the diagnosis and in the precise localization of coronary artery fistulas.