There is increasing evidence suggesting an important role of LDL oxidation in the pathogenesis of atherosclerosis. It has been shown that oxidized LDL is present in vivo and that it is atherogenic in many ways. LDL sensitivity to oxidation depends on many factors. Oxidation occurs mainly in the arterial wall and the methods usually available to measure oxidation are not sensitive enough to detect the minimally oxidized LDL which could be present in the circulation. A more sensitive method would be very useful in clinical trials to test the potential benefits of antioxidant therapy in the prevention and/or the treatment of atherosclerosis. One has to wait for the results of long, prospective, randomized, double blind studies before considering dietary and/or therapeutic recommandations for the use of antioxidants.