Assessment of pulmonary artery pressure is an essential element in the evaluation of children palliated with surgical aorto-pulmonary shunts prior to definitive surgical repair. We report the ease of use and accuracy of a 0.014 inch micromanometer pressure wire for the measurement of pulmonary artery pressures in children with aorto-pulmonary artery shunts. The study population consisted of 11 infants and children with either a 3.5 mm modified Blalock-Taussig shunt from the subclavian artery to the branch pulmonary artery after stage 1 Norwood repair for hypoplastic left heart syndrome or palliative staged repair for tetralogy of Fallot, or a central shunt for pulmonary atresia or double outlet right ventricle. The unique features of the micromanometer pressure wire allowed rapid access and accurate measurement of pulmonary pressures in all patients studied. We conclude that the micromanometer pressure wire is a unique and accurate alternative device for rapid and safe determinations of pulmonary artery pressures in children with aorto-pulmonary artery shunts.