A case of bronchogenic cyst arising from an accessory lobe in a 7-month old baby was encountered at Seoul University Hospital. On exploration, right lung consisted of 4 lobes and a huge cyst was confined to an accessory lobe, which had no bronchial connection. The cyst was filled with jelly-like thick mucus; inner surface was glistening and smooth. Microscopically, the cyst was lined with pseudostratified columnar epithelium. Bronchogenic cyst, moreover, which arising from an accessory lobe is very rare and interesting. And so, case report and review of literature was made.[KTCS 1979;1:9-13]