The authors identify eight areas of potential safety concern during clinical magnetic resonance (MR) imaging. These include (a) biologic effects of the static magnetic field; (b) ferromagnetic attractive "projectile" effects of the static magnetic field; (c) potential effects of the relatively slowly time-varying magnetic field gradients; (d) effects of the rapidly varying radio-frequency (RF) magnetic fields, including RF power deposition concerns; (e) auditory considerations from noise caused by the rapidly pulsed magnetic field gradients; (f) safety considerations concerning superconductive systems, including quenches, use of cryogens, and cryogen storage and handling; (g) psychological effects, such as claustrophobia and anxiety induced because of the examination; and (h) possible effects of the intravenous use of the MR contrast agent gadopentetate dimeglumine. The concerns in each of these categories are elaborated upon, and the available data are presented to clarify their status.