Subxiphoid, two-dimensional echocardiograms (S2DE) were performed and interpreted before diagnostic cardiac catheterization on 59 neonates who weighed 1.3--6.0 kg (median 3.3 kg) and were 1--35 days old (median 4.5 days). The echocardiographic studies were successfully performed on 58 of 59 infants. Using appropriate longitudinal and transverse projections, S2DE permitted simultaneous visualization of the branch pulmonary arteries, proximal thoracic aorta and ventriculoarterial attachments. D-transposition of the great arteries was correctly predicted in all 16 infants with levocardia, situs solitus and atrioventricular concordance. In these patients, the standard left ventricular longitudinal projection demonstrated the bifurcating main pulmonary artery attached to the posterior ventricle; the transverse projection displayed the relationship of the proximal thoracic aorta to the anterior ventricle. The broad acoustical window using the subxiphoid approach in conjunction with a high-frequency focused transducer and a large active-element diameter permitted detailed imaging of intra- and supracardiac structures.