Abstract: OBJECTIVE To explore the correlation of human papilloma virus (HPV) infection and nasal inverted papilloma (NIP) and expressions of Ki-67, p21 and cyclooxygenase-2 (COX-2), and analyze their possible roles in the process of the NIP. METHODS Specimens of 80 cases of surgical and pathological diagnosis of NIP patients with lesions (NIP group) from Jan. 2010 to Aug. 2015 were collected, nasal polyps in 80 cases of patients did nasal polyps surgical resection were set as control group (nasal polyps group). HPV infection was detected by polymerase chain reaction (PCR), and expressions of Ki-67, p21 and COX-2 in tissues of specimens were detected using immune histochemical method. RESULTS Totally 46 cases of HPV were detected in NIP group, with the infection rate of 57.50%, and 21 cases of HPV were detected in nasal polyps group, with the infection rate of 26.25%. The positive rates of Ki-67, p21 and COX-2 in NIP group were all higher than those in nasal polyps group, the difference between the two groups was significant (P<0.05). CONCLUSION HPV infection is closely related with NIP, the infection rate increased significantly with the degree of malignancy and the stage of NIP, and the abnormal expressions of Ki-67, p21 and COX-2 may be involved in the pathogenesis of NIP.