Handling and storage of polyunsaturated lipids is a difficult problem due to oxidation. Oxidation products cause reduction in sensoric quality and can also have negative physiological effects, all of which obstruct the use of otherwise nutritionally important compounds. Therefore it is important to find techniques to prevent this quality deterioration. It is shown in this work that the oxidation of a fish oil can be decreased if the oil is transformed into a microemulsion with ascorbic acid and α-tocopherol used as antioxidants. Tocopherol will be localized in the hydrocarbon chain region whereas ascorbic acid is accumulated in the polar parts of the microemulsion.