Recently, the fruit fly Drosophila melanogaster has been introduced as a model system to study the molecular bases of a variety of ethanol-induced behaviors. It became immediately apparent that the behavioral changes elicited by acute ethanol exposure are remarkably similar in flies and mammals. Flies show signs of acute intoxication, which range from locomotor stimulation at low doses to complete sedation at higher doses and they develop tolerance upon intermittent ethanol exposure. Genetic screens for mutants with altered responsiveness to ethanol have been carried out and a few of the disrupted genes have been identified. This analysis, while still in its early stages, has already revealed some surprising molecular parallels with mammals. The availability of powerful tools for genetic manipulation in Drosophila, together with the high degree of conservation at the genomic level, make Drosophila a promising model organism to study the mechanism by which ethanol regulates behavior and the mechanisms underlying the organism's adaptation to long-term ethanol exposure.