Biopsies from 30 cases of vulvar condyloma, 460 cases of cervical dysplasia, 30 cases of carcinoma in situ and 75 cases of invasive carcinoma of the cervix were screened for the presence of human papillomavirus (HPV) antigen by means of the peroxidase-antiperoxidase method. Positive reaction for HPV was detected in 14 cases of condyloma and 80 cases of dysplasia as a brown intranuclear precipitate in the superficial layer of the epithelium. None of the cases of carcinoma in situ and invasive cancer were positive for HPV. The mean age of the women with HPV-positive dysplasia was significantly lower than that of the women with HPV-negative dysplasia. Condylomatous dysplasia showed a significantly higher positive rate than did noncondylomatous dysplasia. Cases of condylomatous dysplasia with severe stromal inflammation were negative for HPV more frequently than those with mild stromal inflammation.