The relative DNA contents of 164 cellular samples from 59 patients affected by the viral cytopathic effects (VCE) of human papillomavirus (HPV) infection and/or by cervical intraepithelial neoplasia (CIN) and 12 cellular samples from 12 normal donors were analyzed by flow cytometry (FCM) with the aim of correlating the cytometric measurements with the morphologic and etiologic parameters. The unselected group of 59 patients was found to be characterized by statistically significant differences in average ages in the VCE and CIN (31.4 years) and CIN only (44.8 years) subgroups. Of the pathologic samples, 32 (54%) exhibited at least one cell subpopulation with an abnormal DNA content; in all but 2 of those cases, a diploid cell subpopulation was also present. The results indicate a relationship between the FCM ploidy and the morphologic classification, as shown by the increase in the occurrence of subpopulations with abnormal DNA contents from VCE only (38%) to VCE + CIN 1 (57%), to VCE + CIN 2/3 (70%). These results suggest that cytometric parameters, in association with the determination of the HPV types and in parallel to the colpocytohistopathologic criteria, can contribute to a more accurate characterization of cervical lesions in diagnostic and prognostic terms.