Computerized tomographic scanners have gained quick and widespread acceptance in diagnostic radiological practice. The cost of such units is currently about a half million dollars. Technologically, they are one of the most complicated pieces of equipment to be found in a radiology department. Because of the cost and complexity, it seems logical to set up performance specifications, acceptance tests, and a quality assurance program for a CT scanner. Pertinent performance specifications are herein described and discussed. In order to assure that the CT unit does meet specifications, appropriate acceptance tests are likewise discussed. Finally, a basic quality assurance program is outlined with an indication of the tests to be performed and their time frequency.