A rat renin allele (the S-allele) has been identified in Dahl rats which cosegregates with increases in blood pressure. Rats with a double dose of the allele--the salt-sensitive hypertensive rats--have low renin activity compared with the salt-resistant hypertensive rat that does not have this S-allele. Alcohol consumption in rats has also been shown to vary with renin activity, and the possible involvement of renin activity in the genetics of alcohol consumption was suggested by previous work showing that the alcohol-preferring P line of selected rats had low renin levels. In the present study we examined alcohol consumption in a group of inbred Dahl rats, which have a double dose of the S renin allele, and in a group of selected Dahl rats, which have only a single dose of this S-allele. After an initial acclimation period, these two groups were first given daily 1-hr access to ascending concentrations of alcohol (3%, 6%, 8% w/v) over a 34-day period followed by continuous access to alcohol for a further 10 days. Water and food were always available. Regardless of whether alcohol was rationed or continuously available, the rats with the double dose of the S-allele drank significantly more alcohol than the rats that had only a single dose of this allele. These findings suggest that genetically mediated alterations in the renin gene may exert a significant influence on alcohol consumption and may be a component in the etiology of alcoholism.