We report a case of a 20-year-old woman who presented with fever, dry cough and pulmonary consolidation at the left upper lobe on chest radiograph. Fiberoptic bronchoscopy revealed obstruction of the left upper lobar bronchus with exophytic mass and multiple nodular protruding lesions at the left main bronchus. Endobronchial actinomycosis was confirmed by demonstration of sulfur granule through the bronchoscopic biopsy of nodular lesion. Intravenous administration of penicillin G followed by oral tetracycline therapy for 5 months resulted in complete recovery of symptoms which had been present for 3 months prior to therapy. Infiltrative consolidation on the chest X-ray disappeared and all the lesions shown by bronchoscopy were nearly normalized after 6 months only to remain small nodular remnants at the left main bronchus. Endobronchial actinomycosis should be included in the differential diagnosis of endobronchial mass.