Background: A small but significant proportion of cases with atypical squamous cells of undetermined significance (ASCUS) may harbour CIN 2-3, or even invasive carcinoma. Although immediate colposcopy, HPV-DNA testing or expectant management are three recommended options in ASCUS triage, a consensus does not currently exist on which one of these approaches is the most efficient. In this study, we aimed to compare the performance and cost of immediate colposcopy and colposcopy based on the human papillomavirus (HPV) testing for detecting histologically confirmed high-grade cervical intraepithelial neoplasia (CIN) in women with ASCUS. Materials and Methods: Records of 594 women with an index Papanicolaou smear showing ASCUS were retrospectively analyzed. Women in the immediate colposcopy arm were referred directly to colposcopy (immediate colposcopy group, n=255) and those in the HPV triage arm were proceeded to colposcopy if the high-risk HPV (hrHPV) test was positive (HPV triage group, n=339). High grade CIN (CIN2+) detection rate and treatment costs were compared between the groups. Results: The detected rate of CIN2+ was higher in the HPV triage group compared to immediate colposcopy group (8% vs. 1.6%, p=0.011). In the HPV triage group, the total cost, cost per patient, and the cost for detecting one case of high grade CIN were higher than the immediate colposcopy group (p<0.001). Conclusions: In women with ASCUS cytology, HPV DNA testing followed by colposcopy is more costly than immediate colposcopy, but this approach is associated with a higher rate of CIN2+ detection. This findings suggest that HPV DNA testing combined with cervical cytology could reduce the referral rate to colposcopy.