The effect of dietary vitamin E on lipid synthesis from U-14 C-D-glucose and 1-14C-acetate was studied in rat lungs in vitro. One-month-old Sprague-Dawley male rats were fed either a basal vitamin E-deficient diet or one supplemented with 45 ppm vitamin E ad libitum for two months. Glucose oxidation to CO2 by lungs was significantly (p less than 0.05) decreased by the exclusion of vitamin E from the diet. Oxidation of acetate to CO2 was not affected by the presence of vitamin E in the diet. The extent of labeled carbons from both glucose and acetate incorporated into total lipids was significantly lower in the lungs of vitamin E-deficient animals than in those of the supplemented group. However, the relative amounts of phospholipids, neutral lipids are free fatty acids in total lipids, and of glyceryl moiety and fatty acids in total lipids and in phospholipid fraction were not significantly altered by the status of dietary vitamin E. The results suggest a general depression of lipid synthesis in the lungs of vitamin E-deficient rats.