Liquid-based cytology with supplementary human papillomavirus triage (LBC+HPV triage) of low-grade cytological abnormalities may improve the detection of cervical intraepithelial neoplasia (CIN) compared with conventional cytology. To investigate this subject, LBC+HPV triage and conventional cytology were alternated in a population-based screening setting. Cases with abnormal cytology were referred for colposcopy. We compared the performance of LBC+HPV triage [n=4059] and conventional cytology [n=4261] in detecting CIN2 or worse [CIN2+] and CIN3 or worse [CIN3+]. We used logistic regression to assess CIN detection rates and abnormal cytology rates, which yielded unadjusted odds ratios (OR) and corresponding 95% confidence intervals (CI). We computed adjusted ORs from a multivariate logistic regression model that included potential confounders such as age, screening centre and time period. We found similar detection rates of CIN2+ by LBC+HPV triage and conventional cytology; the adjusted OR for the comparison of CIN detection rates was 0.87 (95% CI: 0.60-1.26) for CIN2+ and 1.00 (95% CI: 0.64-1.58) for CIN3+. We also found similar positive predictive values between methods. Thus, there was no advantage in using LBC+HPV triage as compared to conventional cytology in terms of sensitivity, specificity and positive and negative predictive value to detect histologically confirmed CIN2+ and CIN3+. LBC+HPV triage may lead to a reduction in unnecessary work-ups for women with abnormal cytological lesions who are negative for high-risk HPV. It is important to continuously monitor abnormal cytology rates, both when testing a new method, and after the new method has become routine.