Human papillomaviruses (HPVs) are a large group, with over 100 genotypes, of small nonenveloped, double-stranded DNA viruses. HPV types may be classified by infection location on the body each virus tends to infect and its potential for oncogenesis. ?High-risk' and ?low-risk' nomenclature was proposed for HPV genotypes (HPV-HR and HPV-LR). HPV is the major etiologic factor in cervical cancer and is found in the majority of cervical tumors. The major mechanisms through which HPV contributes to neoplastic initiation and progression include the activity of two viral oncoprotein, E6 and E7, which interfere with critical cell cycle tumor suppressive proteins, p53 and pRB. However, HPV infection is not a sufficient cause of cervical cancer and other cofactors contribute to the multi-step process or tumor formation, such as individual genetic variation as well as environmental factors. Recently, prophylactic HPV vaccines have been shown to be effective in preventing infection in young women.