This study was conducted to investigate the effect of dietary protein and fiber levels on the activities of ethanol metabolizing enzymes of liver in ethanol-treated rats. Sprague-Dawley male rats were fed on diets containing two levels of protein(7, 20%/kg diet) and pectin(5, 10%/kg diet). In ethanol experiments, ethanol(25% v/v) was administered by oral intubation(5g/kg body weight) at the same time once a day Control animals received an isocaloric dose of sucrose. The rats were sacrificed after 5 weeks of feeding periods. Alcohol dehydrogenase and microsomal ethanol oxidizing system activities of hepatic tissue were increased more in ethanol-treated groups than in control groups. Increment of activities predominated in normal protein normal fiber group. Aldehyde dehydrogenase activity was decreased in ethanol-treated groups and significantly decreased in normal Protein normal fiber group. Cytochrome P-450 content was significantly increased in ethanol-treated groups and Predominated in normal protein groups. Xanthine oxidase activity was increased in ethanol-treated groups, but not significantly except normal protein normal fiber group. Glutathione content tended to increase in proportion to level of dietary protein and was higher in normal fiber groups than in high fiber groups, whereas it was decreased by ethanol treatment. Lipid Peroxide content was significantly increased in low Protein normal fiber groups.