The role of human papillomaviruses (HPV) as possible agents in the genesis of cervical cancer is reviewed. Several types of HPV (mainly 6, 11, 16, 18, 31, and 33) have been shown to be associated with precancerous processes and cancer of the uterine cervix. HPV also induces pathognomonic abnormality of squamous cells, known as koilocytosis, that may precede or accompany various manifestations of cancerogenesis including invasive cancer. Still, recent studies suggest that HPV infection is quite common in normal people and may prove to be ubiquitous. Hence, the activation of the virus and its ability to interact with cervical epithelium is likely to be due to "patient factors" rather than the presence of the virus per se. The possible mechanisms of virus-epithelial interaction and of the factors that may put a woman at risk for cervical carcinoma are discussed.