Effect of vitamin B_6 depletion on the hepatic compositions of rats fed 70% or 10% casein diet was investegated. Lipid accumulation was observed in the livers of rats 70% casein diet without B_6. The lipid accumulated was twice as high as that of control rats supplemented with B_6 and mainly consisted of glyceride and cholesterol, whereas phospholipid content was unchanged. The lipid accumulation was histologically defined as a fatty degeneration with central globules. Liver protein content was maintained almost at a constant level under any conditions studied.