Eighty five neoplastic tissues of respiratory system in Chinese adult patients were searched for HPV by multiple PCR and in situ hybridization. In 13 of the specimens examined, HPV DNA was identified (15.3%), including 6 of 36 cases of pharyngolaryngeal neoplasms (16.6%) and 7 of 49 cases of lung squamous cell carcinomas (14.2%). Among the 13 cases tumor specimen, most of them were positive for HPV6/11 types and a few were double positive for HPV 6/11 and 16 types. Many tumor cells positive for HPV DNA on in situ hybridization were morphologically similar to those koilocytes in genital condylomas. HPV infection in 85 neoplasms was characterized by the fact that the same genotypes of HPV were detected in upper and lower respiratory tract and that the dominant virus types detected were HPV 6/11 types. The detection rate of HPV was a little higher in the upper than that in the lower respiratory tract and the HPV DNA positive tumors had similar histological appearance. The results suggest that HPV infection in the neoplasms of the upper and the lower airways is related to each other with similar mode of transmission.