Anastomosis of the ascending aorta to the right pulmonary artery, the so-called Waterston shunt, was undertaken as a palliative procedure for children with cyanotic congenital heart disease due to obstruction of the pulmonary outflow tract with reduced pulmonary blood flow. We present the clinicopathological correlations in two patients who underwent construction of Waterston shunts as neonates, and subsequently died of ruptured pulmonary aneurysms in adult life. Rupture should, therefore, be recognized as a late complication of this procedure, and be considered in the long-term follow-up of such patients, especially when the shunted lung is hypertensive.