Between August 1991 and September 2000, 15 patients received a diagnosis of the anomalous origin of the coronary artery from the pulmonary artery, at the Children's Hospital of Wisconsin. All were evaluated initially by transthoracic echocardiography, with subsequent diagnosis confirmation at cardiac catheterization and/or surgery. Seven of the 15 patients were referred in infancy (mean age 4.3 months) with symptoms of congestive heart failure. The remaining 8 patients were older (mean age 7.0 years) at the time of diagnosis, and 7 of those 8 patients were clinically asymptomatic and were referred for evaluation of a heart murmur and/or cardiomegaly on chest radiograph. One older patient, previously healthy, was referred at age 18 for an episode of sudden death while playing basketball. All the older asymptomatic patients had echocardiographic detection of multiple unusual color flow Doppler signals within the ventricular septum, believed to represent septal coronary collaterals, which raised suspicion of a coronary artery abnormality and led to more detailed imaging of the coronary artery anatomy. In the younger infants with congestive heart failure, septal coronary collaterals were less frequent, but did aid in the diagnosis of an anomalous coronary artery when present.