Haemoptysis was the presenting symptom in a 27-year-old male. He had undergone a Mustard operation for connection of complete transposition at the age of 2 years. For 6 months prior to admission, he had complained of dyspnoea without chestpain, and swelling of the fingers during hard physical work. Chest radiography and computer tomographic scans showed normal features of the pulmonary parenchyma, and no sign of cardiomegaly or vascular stasis. Fiberoptic bronchoscopy demonstrated a blood clot in the upper right bronchus, without any associated abnormalities of the bronchial tree. Doppler echocardiography showed obstruction of the superior caval vein, which was verified by cardiac catheterization. Balloon dilation at the site of obstruction increased the diameter of the vein from 0.5 to 1.7 cm, and the mean pressure in the superior caval vein was reduced significantly from 18 to 10 mmHg. The haemoptysis did not recur, and no complaints of dyspnoea or swelling of fingers during physical activity was reported 2 years later. Transthoracic echocardiography undertaken at this time revealed no obstruction of the superior caval vein. We conclude that hemoptysis is a rare complication of increased venous pressure in the upper body of patients with superior caval venous obstruction, which can be treated by balloon dilation or stenting.