C57BL/6J mice, after having been exposed to a free-choice condition between water and aqueous chlordiazepoxide (CDP, 25 mg/100 ml) or between water and ethanol/CDP, showed a significant trend for decreased preference for ethanol when tested 2 weeks later. Similarly, mice previously exposed to a no-choice intake of ethanol showed a significant decrease in ethanol preference when tested subsequently. A long-lasting (greater than 20 weeks) reduction in ethanol selection developed after mice were previously exposed to ethanol/CDP in a no-choice condition. This was also accompanied by a decrease in the subsequent selection of ethanol/CDP, but not CDP. The exact mechanisms for the long-lasting decrease in ethanol selection was unknown, but it was not due to the development of fluid aversion. It is suggested that the combined central effects of ethanol/CDP might be partially responsible.