It has been universally accepted that cervical carcinoma and its closest preinvasive precursor lesion (high-grade cervical intraepithelial neoplasia [CIN] lesions) are caused by a persistent infection with one or more of about 14 high-risk human papillomavirus (hrHPV) types (10, 15). Cervical cancer screening programs rely on the detection and treatment of cervical precancerous (high-grade CIN) lesions and treatable cancer in order to reduce the mortality from this disease. The results of several large population-based randomized screening trials indicate that compared to cytology, testing for about 14 hrHPV types results in marked reductions in the incidence of highgrade CIN lesions and cervical cancers among women who test negative at follow-up (1,4,13,(16)(17)(18). This argues for the implementation of testing for hrHPV in cervical screening programs at increased intervals.The tests for hrHPV that were successfully used in these trials are the commercially available, FDA-approved hrHPV Hybrid Capture 2 assay (hc2) and the consensus primer GP5ϩ/ 6ϩ-PCR with an enzyme immunoassay (EIA) readout (GP5ϩ/ 6ϩ-PCR-EIA) (1,4,13,(16)(17)(18). Both assays target hrHPV types 16,18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68, is additionally targeted by the GP5ϩ/6ϩ-PCR-EIA but is detected by hc2 as a result of cross-hybridization. Given their better performance characteristics relative to those of cytology, these tests can be considered clinically validated for use for cervical screening (14).It has become clear that different assays for hrHPV display different clinical sensitivities and clinical specificities for highgrade CIN lesions and cervical carcinoma (8,9,14,20), and consequently, hrHPV tests different from hc2 and GP5ϩ/ 6ϩ-PCR-EIA are not necessarily useful for cervical screening purposes. In order to facilitate the acceptance and suitability of novel hrHPV assays for cervical screening purposes, guidelines describing the requirements for the use of HPV tests for primary screening have recently been provided by a North American-European collaboration (14). These guidelines propose the use of a clinical validation strategy, based on analysis of the equivalence of the result of an assay relative to that of a clinically validated reference HPV test (i.e., hc2), with samples