Echinococcal or hydatid cyst is one of the most important zoonoses and commonly seen throughout the world, especially sheep and cattle raising areas, but rare in Korea. The causative organism, Echinococcus granulosus, is a small tapeworm and dogs are the usual source of infestation. Lung is the second most common focus for this disease, after liver. Recently, with increasing numbers of Koreans visiting to those endemic countries especially Middle East, the reports of hydatidosis are increasing. Authors experienced two cases of pulmonary hydatid cyst in the 31 year old male and 44 year old male who had a history of spending 2 * 3 years in Middle East. we found them in incidental routine chest X-ray.