This chapter gives an introduction to whole-body computed tomography (CT) screening (WBS). Dr. Harvey Eisenberg began performing WBS with an electron beam CT scanner, using a technique involving a 20-sec scanning acquisition from the neck to the pelvis to include coronary calcium scoring, lung cancer screening, bone densitometry, and an abdominal survey. WBS includes a scan of the head, neck, chest, abdomen, and pelvis. However, WBS is practiced variably in conjunction with other targeted screening examinations such as a chest, abdomen, and pelvis. A serious concern among critics of WBS is that no standards exist for equipment, techniques, personnel, interpretation, or quality for untargeted scans of the whole body. Most practitioners appear to avoid the use of intravenous contrast material because it adds risk, requires monitoring, and add substantial time and cost. However, others observe that many findings are considerably more difficult to detect or characterize without contrast material and that there is limited value to noncontrast examinations for the abdomen. Overdiagnoses represent histologically malignant lesions or other potentially serious diseases that do not progress rapidly enough to harm the patient. Such overdiagnoses, false-positive tests, and incidental findings are the primary flaws of screening because they cause anxiety, procedures, and costs that do not lead to medical benefit. However, among these categories, perhaps incidental findings have received the least attention. Incidental findings may be defined as those that are not related to symptoms or previously detected abnormal physical findings or laboratory results. They are often benign lesions that lead to no symptoms, morbidity, or mortality if ignored. © 2008 Elsevier Inc.