We investigated the prevalences of human papillomavirus (HPV) of type 6, 11, 16, 18, 31, 33, 35 and 42 in 276 cervical tissue samples biopsied from a group of North-Italian women in which a HPV infection of the cervix had been suspected. The specimens were evaluated by conventional histological examination and by HPV typing, using Southern blot hybridization on the extracted DNA. We related different degrees of squamous cervical dysplasia, showing or not viral cytopathic effects, with the HPV types harboured in the lesions. Significant rising of HPV 16 prevalences was observed proceeding from mild to moderate and to severe dysplasias both in presence (r = 0.9623, P less than 0.01) and in absence (r = 0.879, P less than 0.05) of koilocytosis, while an opposite trend was detected for HPV 6 and 11. In our sampling we did not find HPV 35 DNA sequences; in all occasions HPV 31 was associated with mild dysplasias. The absolute prevalences of types 18, 33 and 42 were generally low (from 2 to 3%); they did not show any association with specific histological damage of the cervix or with significant patterns related with the progression of cervical dysplasia.