Hepatic triglyceride (TG) accumulation appeared to vary inversely up to a point with the level of dietary myo-inositol in the absence of dietary choline, and each of the major fatty acids of liver TG was similarly affected. Although the composition of the major fatty acids changed little, 16:1 was generally higher and 18:0 lower in the liver TG of myo-inositol-deficient rats. Furthermore, both the level and the fatty acid composition of non-esterified fatty acids (NEFA) in liver changed dramatically. Supplementation of diets containing myo-inositol or choline with DL-methionine (0.2% by weight) did not significantly influence hepatic TG concentrations. Even when choline was present in the diet at the National Research Council (NRC) requirement (5.4 mmol/kg diet), supplementary myo-inositol decreased further liver TG levels below the levels achievable with choline alone. Dietary myo-inositol was as efficient as choline on a molar basis in preventing the accumulation of TG in liver when compared at 5.4 mmol/kg diet.