Benzodiazepines (BZD) possess anticonvulsant properties that may potentially elevate seizure threshold, inhibit seizure propagation, and alter some of the neurobehavioral effects of electroconvulsive shock (ECS) in animal models. Nevertheless, considerable controversy exists regarding the clinical impact of oral BZD use during electroconvulsive therapy (ECT). The existing literature is contradictory, and all studies attempting to address this topic suffer from important design flaws. Most studies are retrospective and some address only seizure duration. Also, studies examining treatment outcome are difficult to compare because of differing types and dosages of BZD, varied electrode placement and stimulus energy, and lack of information about the relationship of the stimulus energy to the patients' seizure thresholds. While firm conclusions must await further studies, limited data suggest that BZD have the potential to shorten seizure duration and decrease treatment efficacy, particularly with unilateral ECT.