Twenty-one neonates with severe respiratory failure, who met criteria in this center for extracorporeal membrane oxygenation (ECMO), underwent echocardiographic examinations to assess the role of cardiac dysfunction in determining the need for ECMO. The echocardiographic indexes of function included peak aortic and pulmonary flow velocity, aortic and pulmonary acceleration, shortening fraction, velocity of circumferential fiber shortening, right ventricular output, and left ventricular output. Patients were offered a staged treatment protocol using high-frequency oscillatory ventilation (HFOV), followed by ECMO if failing HFOV rescue. Nine patients demonstrated progressive deterioration and required ECMO (group 1); 12 patients recovered without ECMO (group 2). There were no significant intergroup differences in AaDO2, age, weight, gestational age, inotropic support, mean airway pressure, systemic blood pressure, or arterial blood gas parameters. Group 1 had significantly lower pulmonary and aortic peak flow velocities, lower pulmonary acceleration, lower shortening fraction, and lower velocity of circumferential fiber shortening (P less than .05). We found that values for peak pulmonary velocity less than 0.70 m/s with pulmonary acceleration less than 14 m/s2 would predict the need for ECMO in 7 of 9 group 1 patients and recovery without ECMO in 11 of 12 group 2 patients (P less than .01, Fisher's Exact test). We conclude that on initial echocardiographic evaluation, cardiac performance was impaired in those patients who subsequently required ECMO compared with a group of patients with similar severity in gas exchange who recovered without ECMO. We speculate that echocardiographic assessment of cardiac performance in ECMO candidates may prove useful in prediction of the subsequent need for ECMO or expedient transfer to an ECMO center.