All the cytologic and histologic material pertaining to 100 patients who underwent cervical conization for advanced cervical intraepithelial neoplasia (CIN) was reviewed. The revision of the histology of the biopsies and cones showed in 56 cases the association of CIN with viral cytopathic effects (VCE) attributable to human pappiloma virus (HPV) and in 52 the coexistence of a predominantly flat condyloma. The comparison of the two groups of CIN, with and without VCE, showed that in the first the association had favored in 20% of the cases the histologic overestimation of the severity of the lesion. Of the patients with CIN III, 46% showed additional changes due to VCE. The mean age of the patients with CIN and VCE was 39.8 years and that of the patients with CIN was 48.6 (p less than 0.0001). The exocervix was significantly more often involved by CIN + VCE than by CIN alone (p less than 0.00001). Follow-up studies revealed in both groups the same percentage of residual disease and, preliminarily, a trend to a better control of CIN with VCE. New disease developed more often in the group of patients with CIN without VCE. Cytologic sensitivity for VCE in cervical smears was high (95%) in the cases of CIN II and somewhat lower (81%) in those with CIN III. Cytologic follow-up showed the persistence of VCE in 17% of the patients treated surgically for CIN and VCE. The morphologic and clinical features displayed by CIN associated with VCE warrant its recognition as a distinct variant of CIN.