Single acute shortage of pulmonary circulation may cause a life threatening condition, its definitive lack--in consequence of developmental trouble--decreased loading and inclination to infections. It's recognition is most easy by non invasive isotope perfusion pulmonary scintigraphy. Frequency, diagnostic difficulties are a little bit known in Hungary, therefore retrospective investigations were performed by the authors. Examining 961 perfusion pulmonary scintigraphic material of a four year (1990-1994) period-among them that of 52 children-in 8 cases total perfusion-lack of one lung-side was found. Surveyng history of 5 children and 3 adults, besides conventional physical and X-ray suspicion-sings, attention is drawn to signs of non-invasive perfusion and aerosol inhalation pulmonary scintigraphy which are more suitable to demonstrate deviations. In the background of severe circulatory trouble there have been found in one infant grave bronchial stenosis, in 4 children--with different age--arteria pulmonalis agenesia at right, and in 1 young adult (with Fallot-tetralogy), ateria pulmonalis agenesia at left. One of the other adults had bronchial carcinoma, and the other massive pulmonary embolisation. In their diagnostic schedule besides isotope investigations, importance of cardiologic echo-examinations, and the bronchoscopy has been stressed respectively. Catheterisation of the heart is important only in selected cases.