The effect of Ro 19-4603, a novel potent partial inverse agonist of benzodiazepine (BZ) receptors, on voluntary ethanol intake was examined in a rat line selectively bred for ethanol preference (Sardinian ethanol preferring, sP, rats). Ro 19-4603, 1 mg/kg i.p., three times daily, reduced voluntary ethanol consumption by about 40% during 7 days of treatment, but failed to reduce water intake. The results suggest that the GABA/BZ receptor complex may play a role in the reinforcing property of ethanol.