Three samples were submitted from women undergoing routine screening (n=910): two smears (one for routine cytology and one for DNA image cytometry) and a scrape for human papillomavirus (HPV) testing. DNA histograms were classified as suspect in cases of aneuploidy, polyploidy, and/or diploidy with a high proliferation rate. Follow-up was available in 239 cases. The primary end-point was the presence of a high-grade squamous intraepithelial lesion (HGSIL) at biopsy. Seventy women (7.7%) had a high-risk (HR) HPV infection and a suspect DNA profile. In 77 women with cytological abnormalities, 28 HGSILs were detected: four with a prior diagnosis of ASCUS (all HR-HPV infected including three with a suspect DNA profile), three with smears evocative of LGSIL (all with HR-HPV infection and a suspect DNA profile), and 21 with smears evocative of HGSIL (all with HR-HPV infection and 20 with a suspect DNA profile). During the follow-up period, out of 239 women with a cytologically normal smear at first entry, five developed a HGSIL; all were HR-HPV-positive and four had a suspect DNA profile at the first smear. HR-HPV detection alone gives a sensitivity of 100% for the detection of HGSIL, with a specificity of 84.3%, whereas DNA measurement associated with HPV testing significantly enhances the specificity to 95.4%. Thus, the combination of HPV testing and DNA measurement provides a highly sensitive and specific evaluation of the risk of HGSIL on cervical smears. Copyright © 2001 John Wiley & Sons, Ltd.