Repeated transcranial magnetic stimulation (rTMS) is an exciting new technology being used in psychiatric and neurological research in many centres around the world. rTMS has been accepted as a routine treatment of depression in Canada and Israel. To this point, it has been exclusively conducted by medical officers. As knowledge and experience grows, it is probable that professionals with other backgrounds will have the opportunity to play a role. The aim of this paper is to provide information that will be valuable to assistants. Electromagnetic principles are harnessed to deliver electric currents to localized regions of the cortex. rTMS does not involve anaesthesia or seizure. Side-effects appear to be few. Much remains uncertain, however, even including the most appropriate treatment parameters.