A 27-year-old man was admitted to hospital for investigation of haemoptysis. He was a serving member of the Japan Self-Defense Forces. A CXR showed absence of the right hilum, and the right hemithorax was smaller than the contralateral hemithorax. Pulmonary arteriography demonstrated complete absence of the right pulmonary artery. Right heart catheterisation did not show any concomitant cardiovascular malformations, and the patient was diagnosed as having isolated absence of the right pulmonary artery. Bronchial arteriograms demonstrated enlargement and proliferation of the small branches of the right bronchial artery. Bronchofibrescopic examination showed obvious enlargement of the bronchial mucosal vessels with submucosal eruptions and swelling in the right bronchial tree, but not on the left side. Re-examination of the patient's CXR from the previous 9 years revealed a chronological decrease of right lung volume and an increase of the cardiothoracic ratio. Isolated absence of the right pulmonary artery is generally considered to have a good prognosis, but close observation is necessary to monitor the pulmonary haemodynamics.