Qualitative and quantitative effects of the common antioxidants, BHA, BHT, PG and TBHQ on the rate of dissolved free oxygen disappearance in soybean oil during storage were studied. The order of effectiveness was BHA, BHT, PG and TBHQ with TBHQ as the most effective. Statistical analyses of the results showed that the effects of BHA and BHT were not significantly different from each other at the 5% level, but BHA or BHT was different from PG or TBHQ, and PG was different from TBHQ. The antioxidant effectiveness of levels of 0, 50, 100, 150 and 200 ppm BHA, BHT, PG or TBHQ was significantly different from one another at the 5% level. The higher the amounts of antioxidants added, the slower the rate of dissolved oxygen disappearance in the oil.