Genetically modified organism (GMO) using recombinant DNA technique has been exponentially increased, however there are still arguments for the safety of GM foods. The objective of this research was to compare the allergens of GM soybean(Roundup Ready$^{TM}$) with conventional soybeans. Each soybean extracts were prepared as crude extracts, heated extracts, and as heated and simulated gastric quid (SGF)-digested samples to characterize the stability of allergens to physicochemical treatment. Positive sera from 20 soybean-sensitive patients and control sera from 5 normal subjects were used to identify the endogenous allergens in soybeans. Specific-IgE binding activities to each soybean preparations were evaluated by ELISA and immunoblot technique. In ELISA result, IgE binding activities of positive sera to soy crude extracts generally showed two fold higher mean value than those of control sera, how-ever there was no significant difference between GM soybean and natural soybean varieties. Extracted proteins form each of the soybean preparations were separated with SDS-PAGE. The band pattern of GM soybean was very similar to those of natural soybean varieties. Immunoblots for the different soybeans revealed no differences in IgE-binding protein patterns, moreover, disclosed five prominent IgE-binding bands (75, 70, 50, 44 and 34 kDa) in crude extracts, four (75, 70, 44 and 34 kDa) in heated preparations, one (50 kDa) in heated and SGF-digested preparations. These IgE binding bands were consistent with previously reported results on the soybean. These results indicate that GM soybean (Roundup Ready$^{TM}$) is no different from natural soybean in terms of its allergen.gen.