A CASE OF MAC LEOD SYNDROME WHIG WAS DIAGNOSED BY PULMONARY ANGIOGRAPHY. ✓ Selective pulmonary angiography and perfusion scintigraphy were performed to a 28-year old man whose chest X-ray was showing unilateral hypertransradiancy. The left pulmonaray artery was small and there was poor peripheral filling. There was a hypoperfusion defect on scintig¬raphy. Right side pressures and 02 saturations of the heart were normal. A diagnosis of Mac Leod syndrome was made. Spirometric anaysis detected obstruction on the small and medium airways. Mac Leod Syndrome is a rarely diagnosed disease and the patients with unilateral hyperlucent lungs should be investigated by using pulmonary angiography. Rutin muayene esnasında akciğer grafisinde tek taraflı hiperradyolüsen akciğer görülen 20 yaşındaki erkek hastaya selektif pulmoner anjiografi ve akciğer perfüzyon sintigrafisi yapılarak sol akciğerde rudimenter pulmoner arter ve bazallerde daha belirgin olan hipoperfüzyon defekti saptanarak Mac Leod sendromu tanısı konuldu. Bakılan sağ kalp basınçları ve 02 satürasyonlan normal bulundu. Solunum fonksiyon testleri küçük ve orta hava yollarında obstrüksiyonla uyumlu idi. Mac Leod sendromu nadir görülen bir antite olup tek taraflı hiper¬radyolüsen akciğer grafisi olan hastalarda anjiyografık olarak araştırılmalıdır.