Fifty-seven cases previously diagnosed as either dysplasia or carcinoma in-situ by three Japanese medical centers were reviewed and reclassified as either condyloma, CIN I, II, III or squamous metaplasia. Of 46 cases previously diagnosed as mild or moderate dysplasia (CIN I-CIN II) 13 were reclassified as condylomata. Immunoperoxidase localization of human papilloma virus antigens was negative in 21 cases of CIN and positive in 3 of 5 cases classified as condylomata. The prevalence of human papilloma virus infection in these Japanese women appears to be similar to that reported in other countries including Western Europe and the United States.