We systematically reviewed the literature on the accuracy of new technologies proposed for breast cancer screening. Four potential tests were identified (ultrasound, magnetic resonance imaging (MRI), full-field digital mammography (FFDM), and computer-aided detection (CAD)) for which primary studies met quality and applicability criteria and provided adequate data on test accuracy. These technologies have been assessed in cross-sectional studies of test accuracy where the new test is compared to mammography. Ultrasound, used as an adjunct to mammography in women with radiologically dense breasts, detects additional cancers and causes additional false positives. Magnetic resonance imaging may have a better sensitivity (but lower specificity) than mammography in selected high-risk women, but studies of this technology included small number of cancers. Computer-aided detection may enhance the sensitivity of mammography and warrants further evaluation in large prospective trials. One study of FFDM suggests that it may identify some cancers not identified on conventional mammography and may result in a lower recall rate. The evidence is currently insufficient to support the use of any of these new technologies in population screening, but would support further evaluation.