Placental transmogrification is a peculiar clinical entity of the lung of uncertain etiology. We report 2 cases of pulmonary placental transmogrification in 2 patients of different nationalities. Both of them had no history of smoking or chronic lung disease. The main presentations were dyspnea and chest pain. Radiologic studies showed a unilateral giant bulla in both patients; additional pneumothorax was present in only 1patient. They underwent surgical bullectomy. Histopathologic studies revealed the presence of intracystic placenta-like villous structures and a diagnosis of placental transmogrification was made. Placental transmogrification should be considered in cases of unilateral bullae.