A reliable application of the polymerase chain reaction (PCR) for detection of the human papilloma virus (HPV) genotypes in cervical smears and biopsies was developed. Primers flanking the HPV cloning site were used to avoid detection of cloned HPV plasmids. These anticontamination primers were used for the specific detection of HPV 6, 11, 16, 18, and 33 in cervical scrapes that had been tested previously for HPV with a combined modified filter in situ hybridization (modified FISH) and dot blotting procedure. The PCR appeared to be superior. Two groups of women were screened for HPV genotypes. Group A consisted of women belonging to a regularly screened population, and group B contained women attending a gynaecological clinic. It appeared that the overall prevalence of HPV in cytologically normal scrapes in the first group was 6%, whereas in the second group 12% was found. In scrapes with cytological dysplasia, the prevalence of HPV in group A and B was approximately 40% and 60%, respectively. HPV 16 was present predominantly. In biopsies of squamous cell carcinomas of the cervix uteri, an HPV prevalence rate of 90% was found, all of which contained only HPV 16 and 18. These data indicate an important role for HPV detection in the screening of cervical scrapes to identify women with an increased risk of cervical cancer.