The prevalence of human papillomavirus (HPV) genotypes was investigated by the polymerase chain reaction (PCR) method in cytologically normal and abnormal cervical scrapes obtained from asymptomatic women (n = 1,346), participating in a triennial screening program for cervical cancer, and from a gynecological outpatient population (n = 593). In the symptom-free population oncogenic HPV types 16, 18, 31 and 33 were present in 1.5% of cytologically normal scrapes, while the overall HPV prevalence rate was 3.5%. Significantly, higher HPV prevalence rates of 7% (oncogenic HPV; p less than 0.01) and 14% (all HPV; p less than 0.01), respectively, were found in cytologically normal scrapes of the gynecologic outpatient population. It appeared that in this outpatient group 78% of the smears containing HPV 16 and 18 were associated with a history of cervical pathology, i.e. cervical intraepithelial neoplasia grade I to III. In smears with mild and severe dysplasia and smears suspected of carcinoma in situ from both populations, the overall HPV prevalence was 70%, 84% and 100%, respectively. In all squamous-cell carcinomas of the cervix (n = 50) HPV was detected. Frequencies of HPV 16 and 18 increased from 41% in mild dysplasia to 94% in cervical carcinomas. Since a low prevalence of HPV was found in cytomorphologically normal cervices of women without a clinicopathological history, the findings in this study suggest that HPV detection in population-based screening programs for cervical neoplasia can be an important tool in identifying women who are at risk of developing dysplasia and cervical cancer.