We report a case of a 70-year-old woman who presented with mild exertional dyspnea and cough. Fiberoptic bronchoscopic findings revealed an endobronchial polypoid lesion with stenotic bronchus. The lesion was very similar to endobronchial tuberculosis. Histologic examination of the biopsy specimen demonstrated Actinomyces infection. There was a clinical response to intravenous penicillin therapy. Primary endobronchial actinomycosis must be considered in the differential diagnosis of an endobronchial lesion, especially endobronchial tuberculosis in Korea.