The purpose of this study was to investigate the antioxidant and synergistic effects upon different concentrations(0.02, 0.1, l%) of histidine and alanine in soybean oil during incubation at 6$0^{circ}C$. Acid value(AV), peroxide value (POV) and thiobarbituric acid(TBA) value of each oil was monitored. Histidine and alanine showed antioxidative effects in all concentrations. In the case of the incubating antioxidative effect of histidine was lower than that of TBHQ. That of alanine was considerably higher than that of $alpha$-tocopherol, but was lower than that of histidine. Synergistic effects among histidine, alanine and some food antioxidants were shown to exist available in all substrates and the best effect was shown in substrate added compound of histidine and $alpha$-tocopherol.