The potential bioeffects associated with magnetic resonance (MR) procedures result from exposure to the static, gradient, and radiofrequency electromagnetic fields. Each electromagnetic field represents a possible health risk at sufficiently high levels of exposure. The presence of certain biomedical implants and devices may pose hazards for patients undergoing MR procedures. Additionally, other safety issues must be considered for patients in the MR environment. This review article discusses the bioeffects of MR exposures and provides an overview of safety considerations, with an emphasis on information pertinent to cardiovascular patients.