Two trials were conducted to determine the effect of several nutrients on liver fat, egg production and egg weight of White Leghorn hens.One trial used a diet containing adequate protein and supplemented with methionine, while the other used a 15.9% protein basal diet unsupplemented with methionine. A third trial was conducted to study the effect of temperature on liver fat.Choline supplementation or a combination of choline and vitamin B12 caused an increase in egg production and egg weight, and a decrease in liver fat. A combination of methionine and vitamin B12 caused a decrease in liver fat, but the decrease was not as large as that obtained by feeding choline.Supplementing the diet with inositol, riboflavin, pyridoxine, Ca pantothenate, vitamin E, folic acid, biotin or terramycin had no effect on liver fat.Liver fat was significantly higher in hens kept at a high temperature than for those kept cool. Supplementing the diet with a combination of vitamins reduced liver fat in hens kept under hot conditions, but not when they were kept under cool conditions.