The aim of the study was to compare the histological outcome of the cone specimens with the diagnoses of the preoperative biopsies, to assess the distribution of histological features consistent with human papillomavirus (HPV) infection and, finally, to analyse the impact of cellular HPV features on classification of cervical intraepithelial neoplasia (CIN). The study comprised a population of 317 women treated for CIN by laser conization during the period 1983-85. A total of 634 cervical specimens (317 preoperative biopsies and their corresponding cones) were studied retrospectively for CIN classification and examined for morphological signs of HPV infection. For presentation of the results, we used a modified terminology for CIN. Low-grade (LG) CIN included borderline lesions and CIN I, while high-grade (HG) CIN included CIN II and CIN III. The blinded histopathological review revealed HG CIN both in the preoperative biopsies and the cones in 71% of the cases. LG CIN or benign lesions were found in the preoperative biopsies and their corresponding cone specimens in 6% of the study population. HPV features were present in 65% of the preoperative biopsies, and were most prevalent in women under 29 years of age (p < 0.001). Thirteen percent of the total biopsy material was downgraded. The downgrading was most prevalent among original CIN II (p = 0.009) and HPV-negative biopsies (p < 0.001). This study demonstrates that CIN lesions are frequently associated with HPV features, which are significantly more prevalent in the youngest women. Concomitant HPV features do not influence the CIN classification.