Influences of diet composition on the activities of two lipogenic enzymes, malic enzyme and ATP-citrate lyase, and on the hepatic triglyceride accumlation were investigated in rats. In addition, the effect of chronic administration of ethanol on these enzymes and hepatic triglyceride accumulation were studied. The results were summarized as fallowing. 1) The activity of malic enzyme in the liver of rat fed high-fat (HF), low-carbohydrate (LC) and high-carbohydrate (HC) diet groups was 62%, 55% and 155% of that of the normal level, and the ATP-citrate lyase activity was 22%, 31% and 44% of that of normal level, respectively. These changes of the lipogenic enzyme activities were not altered by chronic administration of ethanol to the rats. 2) Average content of triglyceride in the liver of rat in normal diet group was 9.27mg per g. of liver, 16.37mg in the normal diet plus ethanol treated group, 37.79mg in the HF diet group, 75.7mg in the HF plus ethanol treated group, 14.78mg in the LC diet group, 17.87mg in the LC diet plus ethanol treated group, 11.61mg in the HC group, 14.92mg in the LC diet plus ethanol treated group. These results, shows that the administration of ethanol was increased hepatic triglyceride content only in the high fat diet group. 3) Free fatty acid concentration was increased in the serum of rats free fatty acid concentration was decreased by 40% in the high carbohydrate group, may be due to the increased or decreased mobilization of lipid from peripheral adipose tissue. 4) No total phospholipid content in the serum of rat was observed among above different diet and plus alcohol treated group. It is therefore apparent that ethanol administration induces the hepatic accumulation of triglyceride in the HF diet group, whereas it reduces the hepatic accumulation of triglyceride and serum free fatty acid level in the HC diet group.