Since its introduction in 1938, electroconvulsive therapy (ECT) has remained an important treatment for selected serious neuropsychiatric illnesses and continues to be one of the most effective treatments in psychiatry. ECT has evolved into a technically sophisticated procedure with a proven track record of safety. For this review, the authors relied heavily on the database from the APA Task Force Report on ECT (2001), updated with additional searches of computerized literature databases for the period 1999-2003. The review is necessarily a selective one, given the exponential growth of literature in the field. The authors attempt to summarize key areas of ECT practice, informed by relevant research findings and expert consensus when applicable. The authors also point out areas of controversy and gaps in our present knowledge. Although this review summarizes the scientific literature about the use of ECT generally, emphasis is given to describing literature pertaining to the treatment of geriatric patients when such information is available or when older patients or the disorders from which they suffer merit special consideration.