The literature dealing with electrophysiological research in individuals at risk for alcoholism is reviewed. Event-related potential (ERP) and electroencephalographic (EEG) differences between family-history-positive (FHP) and family-history-negative (FHN) men have been reported both prior to the ingestion of alcohol and following alcohol challenge doses. At present, the most robust of these electrophysiological findings is the lower P3 amplitude of the ERP, which has now been replicated in several laboratories. This perhaps provides a phenotypic marker, distinguishing those at risk for alcoholism. However, its specificity for alcoholism and the role of gene-environment interactions in the development of alcoholism remain to be determined.