This child was referred for investigation of an easily rising pulse under strain. ECG and chest radiograph show no signs of cardiac loading nor had the murmur been detected earlier. On auscultation a quiet systolic flow murmur is heard in the pulmonary area. It resembles the physiological sound but is longer and pansystolic. The second heart sound is clearly and constantly split. The finding is well depicted on the phono- and spectrograms. Echocardiography showed a 13 x 8 mm secundum-type ASD. Pulmonary artery flow velocity was 1.7 m/s, that of aorta 0.9 m/s. Because the ASD secundum murmur is caused by increased pulmonary artery flow, the sound is sometimes difficult to distinguish from the physiological sound. In such cases attention should be paid on the possible splitting of the second heart sound. After this investigation this child was referred for corrective surgery. Age 11.3 years. Area of auscultation: left second ic (LIC2).