This report provides assistance in how to organize adequate and appropriate training for personnel working with ionizing radiation. It is primarily intended to be used by trainers and training providers, and covers among other topics the various methods of training provision and gives advice on the development and organizational aspects associated with the management of training activities. It complies with the requirements laid down in Safety Series No. 115, International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (1996). It supersedes Technical Reports Series No. 280, Training Courses on Radiation Protection (1988).