Pulmonary eosinophilic granuloma, a rare form of Langerhans cell histiocytosis confined to lung, is a granulomatous disorder of the lung of unknown cause. Eosinophilic granuloma is clinically suspected in the presence of diffuse pulmonary infiltrate and bony involvement. The radiologic findings of lung are variable according to the stage of disease. Therefore pathologic diagnosis is essential for confirmative diagnosis. Pathologically it is characterized by proliferation of Langerhans cells mixed with lymphocytes, plasma cells and eosinophils. Over 90% of patients are cigarette smokers, and it is rarely reported in non-smokers. We report two cases of eosinophilic granuloma manifested as spontaneous pneumothorax in two young patients. Both were active cigarette smokers and subsequently confirmed as eosinophilic granuloma with open lung biopsy and Video associated thoracoscopic surgery (VATS).