Among human papillomavirus (HPV) types found in humans, there is a strong association between HPV 16, 18, 31, and 33, and cervical cancer. The relationship between various grades of dysplasia and HPV type is less clear. To elucidate this point, the authors tested 476 cytological and histological samples from cervix with polymerase chain reaction (PCR) for HPV using consensus primer My 09-11 and type-specific primers. All cases were divided into groups on the basis of cytology: "normal cases" (ie, women with other disease than cervical intraepithelial neoplasia [CIN]), and CIN I, II, and III. Out of the "normal cases," in which women with a previous history of condyloma and dysplasia were included, 69% had HPV with type 6 as the most common one. Of all CIN I cases, 71% were HPV positive, and HPV type 6 and 16 were equally common. In CIN II cases, HPV 16 was the most common type, whereas HPV 6 accounted for only 7.5% of cases in this group as single virus type. HPV 16 was also the most common type in the CIN III group, followed by type 33. Double and even multiple infections occurred in all groups.