Cervical intraepithelial neoplasia grade 3 (CIN 3) is treated surgically. Follow-up of these patients is important to ensure successful treatment. The present study was undertaken to determine whether human papillomavirus (HPV) testing can be used to discriminate patients who will have recurrences from those who will not. It is composed of 26 patients who presented with recurrences of CIN and 22 patients who remained disease-free after treatment. DNA was extracted from paraffin-embedded cone biopsies of incident CIN 3, their corresponding follow-up Pap smears taken 3 months postoperatively, and their secondary cone biopsies of the recurrent lesions. The extracted DNA were then analyzed by PCR for the presence of HPV. The posttreatment cervical smears in the recurrent group had a (25/26) 96% HPV prevalence, while HPV DNA was not detectable in any of the 22 patients in the control group. The HPV types in both the initial and recurrent lesions correlated very well. This suggest that most recurrences are likely to be due to persisting lesions or subclinical HPV infections that had not been completely removed. Cytology alone was not sufficiently sensitive to discriminate the patients at risk for recurrences. It appears that HPV testing can be useful to monitor the therapeutic result.