The inflation phenomena due to brief microwave irradiation on albuminous materials with alimited amount of water involve remarkable changes in their rheological properties. To investigatethe inflation phenomena and the changes in physico-chemical properties of the maerials, whole egg and egg albumin compounded with various amount of water were heated by microwave andconductive ovens and examined for some properties, and the following results were obtained :(1)Whole egg and albumin, ranged in 30-40% of their initial water content, were the most inflatable asindicated by higher velocities of temperature-rise and water evaporation. (2) The samples inflated bymicrowave heating were different from those by conductive heating in the following points. (1), The rate of enzymatic digestion with trypsin was much higher. (2)The rate of deuterium-protium exchange was higher at the earlier heating stage. (3) The amount of extractive protein were ratherlowered of the samples in the limited water condition. (4) The release of lipid from whole egg onmicrowave heating was prevented much more than that on conductive heating.