Absent pulmonary valve with intact ventricular septum is a rare congenital anomaly. Most cases are not diagnosed until years after birth, although several cases have been reported in the literature in which cardiorespiratory distress developed during the neonatal period. We present a patient who showed improvement after fairly conservative therapy to alleviate the pulmonary vascular resistance, with ultimate palliative surgery. The aneurysmal dilatation of the pulmonary artery was for the most part confined to the proximal portion of the trunk, possibly because the ductus arteriosus was patent. The literature is reviewed.