Two-dimensional (2-D) and Doppler echocardiographic features of three cases of coronary arteriovenous fistula (CAVF) were analyzed. The final diagnosis was confirmed by coronary angiography in each case. In cases 1 and 2, the CAVF arose from the right coronary artery and drained into the right atrium and right ventricle, respectively. The origin and draining site of the CAVF could be visualized by 2-D echocardiograms. The Doppler studies revealed a unidirectional flow within the lumen of the CAVF. In case 3, with a small CAVF originating from both the right coronary artery and left circumflex artery draining into the main pulmonary artery, no abnormal vascular structure could be detected by the 2-D echocardiogram; with Doppler study, a diastolic as well as systolic flow signal directed toward the distal pulmonary artery could be detected.