Five milligrams of intravenous diazepam given prior to contrast media injection statistically significantly reduced the incidence of contrast media-associated seizures from 16% to 2% in a prospective, randomized series of glioma patients. Factors related to increased risk of contrast media-associated seizures are (1) prior seizure history due to glioma and/or prior contrast media and (2) prior or concurrent brain antineoplastic therapy. Factors not related to an increased risk of contrast media-associated seizures are (1) contrast media dosage, (2) type or grade of glioma, and (3) computerized tomographic appearance of the glioma. Theories regarding the etiology of contrast media-associated seizures are discussed.