The effects of vitamins A and E on rat tissue lipids were studied by feeding groups of rats a factorially arranged series of diets involving 3 levels of vitamin A (25 IU/wk, 200 IU/wk, 1000 IU/wk) and 4 levels of vitamin E (0.00 mg/wk, 0.35 mg/wk, 0.70 mg/wk, 3.50 mg/wk). Following the 10 wk experimental period, the cholesterol and total lipids concentration in the serum and the liver of the animals were determined, as well as the vitamin A content of the liver. A statistical analysis of the data indicated that increasing dietary vitamin A significantly lowered the serum and liver cholesterol and increased liver total lipids and vitamin A storage at vitamin E dietary levels 0.00 to 0.70 mg/wk. For all levels of dietary vitamin A studied, increasing dietary vitamin E significantly lowered serum cholesterol, lowered serum and liver total lipids, increased liver vitamin A storage, and was dependent on the specific vitamin A dietary level for its effect on liver cholesterol. A distinct interaction of the vitamins A and E was found to affect serum cholesterol and liver cholesterol, total lipids, and vitamin A storage. The interaction most apparent at vitamin E dietary levels of 3.50 mg/wk.