Although the low incidence of immediate-type gadolinium-based contrast agent (GBCA) allergic reactions is widely known, preventing these reactions and properly managing them to reduce their adverse sequel can improve the already exceedingly favorable GBCA safety profile. This review article should help those who order, supervise, or administer GBCA contrast agents, including recognizing and handling allergic reaction risks intrinsic to their use. Areas of focus include factors indicating increased allergic reaction risk, patient selection strategies, skin testing, premedication, and treatment of adverse events.