A 79-year-old female presented with persistent dry cough, and a chest radiograph showed a mass shadow in the right upper lung. Bronchoscopic examination revealed that the right main bronchus was severely obstructed by a polypoid tumor, which was diagnosed pathologically as squamous papilloma. After the failure of the attempted endobronchial snare to remove the tumor, right upper lobectomy was performed. The polymerase chain reaction (PCR) examination showed the presence of human papilloma virus type ll DNAin the resected tumor, suggesting that this virus was the cause of this solitary squamouspapilloma of the lung. (Internal Medicine 38: 817-819, 1999)