The Radiation Protection Bureau has set out guidelines for the testing of diagnostic x-ray equipment and facilities. This guide provides information for the x-ray inspector, test engineer, technologist, medical physicist and any other person responsible for verifying the regulatory compliance or safety of diagnostic x-ray equipment and facilities. Diagnostic x-radiation is an essential part of present day medical practice. The largest contributor of irradiation to the general population comes from diagnostic x-radiation. Although individual irradiations are usually small, there is a concern of possible excess cancer risk when large populations are irradiated. Unnecessary irradiations to patients from radiological procedures can be significantly reduced with little or no decrease in the value of medical diagnostic information. This can be achieved by using well designed x-ray equipment which is installed, used and maintained by trained personnel, and by the adoption of standardized procedures. In general, when patient surface dose is reduced, there is a corresponding decrease in dose to x-ray equipment operators and other health care personnel. 2 tabs., 4 figs.