This study investigated the value of color flow mapping in documenting normal pulmonary venous return in neonates with persistent pulmonary hypertension who were candidates for extracorporeal membrane oxygenation (ECMO). Forty newborn infants with persistent pulmonary hypertension underwent conventional (two-dimensional and Doppler) echocardiography and color flow mapping. Of 25 candidates for ECMO therapy, 18 subsequently received it. Conventional echocardiography demonstrated normal pulmonary venous return in only 21 of the 40 patients. In all 40, however, color flow mapping demonstrated normal right and left pulmonary venous drainage entering the left atrium. In three other patients with total anomalous pulmonary venous return, conventional echocardiography demonstrated the anomalous pulmonary venous pathways, and color flow mapping did not show jets emanating from the left atrial wall; the left atrium was shown to fill exclusively from right to left shunting through the foramen ovale. We conclude that color flow mapping is superior to conventional echocardiography for verifying normal pulmonary venous return in neonates with persistent pulmonary hypertension.