More than 13 years have passed since HPV DNA was first detected in cervical cancer. Vigorous studies, basic and clinical, during these years have elucidated the causative relationship of HPV with cervical cancer. There are more than seventy types of HPV, among which types 16, 58, 52, 18 and 31 were detected from cervical cancers obtained from Japanese women. HPV-DNA was detected from more than 90% of the cases of cervical dysplasia whose types were shown to be more widely distributed than those of cervical cancer. The serum antibody to HPV has been detected by Western blot or ELISA using fusion protein as antigen. Anti HPV-16/E7 antibody was detected in cervical cancer patients at significantly higher rates than in control patients. The expression of E6/E7 genes of high-risk HPVs (16, 18 and others) seems to be an essential but not a sufficient factor for malignant conversion of the cervical epithelium.