C57BL/6 and BALB/c mice were tested for ethanol preference at three ages (7-9 mo., 14-16 mo., 22-24 mo.). Eight ethanol concentrations (4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%) were used. A reduction in ethanol preference with increasing age was seen in the C57BL/6 mice, but not in the BALB/c animals. For C57BL/6 mice the largest difference in ethanol preference occurred between the 10% and 18% ethanol solutions. It was found that the ethanol preference of the 14-16 mo. C57BL/6 mice was similar to the 7-9 mo. old C57BL/6 mice at the first 5 concentrations. For the remaining concentrations the 14-16 mo. mice more closely resembled the 22-24 mo. mice in ethanol preference. The results of this study suggested that increased age does not simply result in a reduction in ethanol preference, but is a function of the genotype and concentration of the ethanol solution.