The possibility of using Gamma irradiation to modify the functional properties and deactivate the trypsin inhibitor of the legumes and their soups were studied in five Egyptian legumes; Faba beans, Lentils, French beans, Cowpeas and Chickpeas. This effect was illustrated in two levels. The first level was at 1 KGy which is considered to be safe and appropriate dose for insect disinfestation; the other doses were applied at 5, 10 KGy. There was a dose depended relationship between (P<0.01) the emulsification and oil absorption capacity and the absorbed dose. It seems that irradiation modify these properties. The data also showed a changes in the trypsin inhibitor destruction rate which was getting higher as a result of increasing the adsorbed doses. at (5, 10 KGy). Combining 1 KGy dose; the safe and appropriate for insect disinfestation with other traditional process led to complete deactivation of this inhibitor. The proposed mathematical model showed that Gamma irradiation affected the trypsin inhibitor through lowering the t1/2 half life and D value of the inhibitor.