Ethanol metabolism as a function of age was assessed in male Sprague-Dawley rats. The ethanol metabolic rates decreased linearly with advancing age. It was also observed that a linear decrease in hepatic alcohol dehydrogenase activity occurred as a function of age. The decreased enzyme activity could be the biochemical mechanism underlying changes in ethanol metabolism. Impaired ethanol metabolism may produce increased pharmacologic effects in older subjects due to increased blood ethanol levels.