Objective: This study aims to improve the diagnostic and therapeutic efficacy through analysis of clinical and radiographic characteristics in pulmonary endometriosis. Materials and Methods: This retrospective study was conducted from January 1998 to December 2008. The clinical and radiographic characteristics of five patients diagnosed as pulmonary endometriosis were evaluated. Results: Among the five female patients of reproductive age, one case presented with recurrent pneumothorax, four cases presented with recurrent hemoptysis. Episode of pneumothorax and hemoptysis had the close association with the menstrual cycle. Except for pneumothorax case, the computed tomography (CT) scans during menstruation showed patchy opacification or infiltration (n=4). Histopathologic examination of the resected specimen conformed typical endometrial tissue in the lungs. Misdiagnosis occurred involving spontaneous pneumothorax (n=1), pulmonary tuberculosis (TB) (n=3), and bronchiectasis (n=1). Conclusion: Pulmonary endometriosis is prone to misdiagnosis. The combination of medical history and CT scans in association with menstrual cycle was useful to make the differential diagnosis after effective diagnostic treatment of hormone therapy.