Until now little attention has been paid to the potential of MR imaging in congenital heart disease of the newborn. ECG-gated MRI was therefore performed at 0.5 tesla in 23 newborns (mean age 7.5 days) with suspected congenital heart disease. Two newborns were controlled after surgery (switch, Blalock-Taussig procedure). All had undergone prior evaluation by two-dimensional Doppler echocardiography (2-D DE). MR imaging was of a satisfying quality in all but one newborn. The aim of this study was to assess complementary information provided by MRI in comparison to 2-D DE. Pre-operatively MRI missed some abnormalities shown by 2-D DE: one coartaction, one ductus arteriosus and one pulmonary atresia. MRI demonstrated lesions that echocardiography had either failed to visualize or found inconclusive, including double aortic arch (one patient), muscular ventricular septum defect (two patients) and severe ductus arteriosus (one patient). In one of the two patients with a ventricular septum defect, angiography was avoided and in the other patient it merely confirmed the MRI results. Post-operatively, MRI demonstrated information complementary to that obtained from to 2-D DE: (1) clearly visualizing the reinsertion of the coronary arteries in the 'switched' transposition of the great vessels, (2) appreciating the diameter and patency of the palliative shunt in the Blalock-Taussig procedure.