Coronary arteriovenous fistula (CAVF) is a rare condition defined as an anomalous termination of the coronary arteries. The etiology of CAVF is either congenital or acquired, and iatrogenic CAVF is most commonly caused by cardiovascular surgery or percutaneous intervention. Most of the prenatally diagnosed CAVFs were related to complex heart disease, and only few cases of an isolated CAVF have been reported to date. We successfully diagnosed an isolated CAVF by fetal echocardiography at 25.3 weeks of gestation. Accurate prenatal diagnosis resulted in the prompt decision for postnatal surgical correction, and the neonate thrived well without any complications.