Magnetic resonance is an extremely powerful imaging tool which does not expose patients to ionizing radiation. However, there are risks associated with the MR environment which all staff must be aware of and eliminate. The aim of this article is to highlight the well known and not so well known potentially adverse interactions. Although many safety investigations have been carried out at up to 1.5T, the reader will be reminded that as many centres install magnets of 2.0T and above, much of the current safety literature cannot be simply extrapolated to these higher field strengths and further investigations will be required to reassure staff and patients of the limits of their safe use.