HPV-induced changes in the portio vaginalis uteri can and have lead to misinterpretations since they frequently occur in combination with or resemble precancerous or cancerous changes. The morphological peculiarities and growth patterns of koilocytotic changes in the portio vaginalis uteri are described. Among 684 conizations performed, 169 (24.7%) were found to have features of an HPV-infection. Of these, 75.7% also had preneoplastic or neoplastic changes. Review of the cytological findings revealed that in 66.7% of the cases with histologically verified koilocytosis a false positive finding of malignancy had been recorded.