Background: The ALTS (atypical squamous cells of undetermined significance [ASCUS] and low-grade squamous intraepithelial lesion [LSIL] Triage Study) suggests that, for women diagnosed with ASCUS, human papillomavirus (HPV) DNA testing followed by referral to colposcopy of only those women with oncogenic HPV (i.e., HPV DNA testing) is as effective at detecting cervical intraepithelial neoplasia (CIN) 3 or cancer (CIN3+) as referring all women with ASCUS for immediate colposcopy. We conducted a cost-effectiveness analysis of the ALTS trial to determine whether HPV DNA testing is a cost-effective alternative to immediate colposcopy or conservative management with up to three cytology examinations. Methods: Data from the ALTS trial were used in conjunction with medical care costs in a short-term decision model. The model compared the incremental costs per case of CIN3+ detected as measured by the incremental cost-effectiveness ratio (ICER) for the following management strategies for women with ASCUS: immediate colposcopy, HPV DNA testing, and conservative management with up to three cytology examinations. Results: The least costly and least sensitive strategy was conservative management with one repeat cytology examination using a threshold of high-grade squamous intraepithelial lesion (HSIL) for referral to colposcopy. Compared with this strategy, triage to colposcopy based on a positive HPV DNA test result had an ICER of $3517 per case of CIN3+ detected. Immediate colposcopy and conservative management with up to three repeat cytology visits detected fewer cases of CIN3+ and were more costly than HPV DNA testing. Immediate colposcopy became cost-effective at $20 370 compared with HPV DNA testing only if colposcopy and biopsy were assumed to be 100% sensitive. Conclusions: HPV DNA testing is an economically viable strategy for triage of ASCUS cytology. The less than perfect sensitivity of colposcopy and biopsy needs to be accounted for in future clinical guidelines and policy analyses.