Objective To provide evidence-based consensus guidelines for the management of women with cervical cytological abnormalities and cervical cancer precursors. Participants A panel of 121 experts in the diagnosis and management of cervical cancer precursors, including representatives from 29 professional organizations, federal agencies, and national and international health organizations, were invited to participate in a consensus conference sponsored by the American Society for Colposcopy and Cervical Pathology (ASCCP). Evidence and Consensus Process Guidelines for the management of women with cervical cytological abnormalities were developed through a multistep process. Starting 6 months before the conference, working groups developed draft management guidelines based on formal literature reviews of English-language articles published in 1988-2001, as well as input from the professional community at large, obtained using interactive Internet-based bulletin boards. On September 6-8, 2001, the ASCCP Consensus Conference was held in Bethesda, Md. Guidelines with supporting evidence were presented and underwent discussion, revision, and voting. Conclusions Management of women with atypical squamous cells (ASC) depends on whether the Papanicolaou test is subcategorized as of undetermined significance (ASCUS) or as cannot exclude high-grade squamous intraepithelial lesion (HSIL) (ASC-H). Women with ASC-US should be managed using a program of 2 repeat cytology tests, immediate colposcopy, or DNA testing for high-risk types of human papillomavirus (HPV). Testing for HPV DNA is the preferred approach when liquid-based cytology is used for screening. In most instances, women with ASC-H, low-grade squamous intraepithelial lesion, HSIL, and atypical glandular cells should be referred for immediate colposcopic evaluation.