EVIDENCE has accumulated indicating that: (1) vitamin E functions, at least in part, as a lipid antioxidant; (2) unrelated substances having antioxidant activity can alleviate or prevent some of the symptoms of vitamin E deficiency1; (3) selenium compounds also can alleviate or prevent some of the symptoms of vitamin E deficiency2; (4) the ingestion of selenium oxide renders tissues less susceptible to oxidative attack3; (5) some seleno-amino-acids have antioxidant activity in aqueous lipid emulsions4. The experiments reported here were undertaken to determine whether seleno-amino-acids could act as antioxidants in anhydrous fats and oils.