Epidemiological studies on the association between human papillomavirus (HPV) and cervical cancer are reviewed. Studies using HPV DNA hybridization methods to assess the presence of viral markers have yielded compelling evidence that HPV has a causal role in the disease: the association is strong, consistent and specific to a limited number of viral types. A dose-response relationship has been reported between increasing estimated viral load and risk of cervical cancer. Indirect evidence suggests that HPV DNA detected in cancer cells is a good marker of HPV infection occurring before cancer development. An increased risk for progression to more advanced CIN lesions has been reported among HPV 16/18-positive women as compared to women with other HPV types or to women without any viral DNA.