The effect of electron beam irradiation at different radiation doses (2, 5, 10, 15, and 20 Mrad) on trimethylol propane trimethacrylate (TMPTMA), ethylene vinyl acetate (EVA, 12% vinyl acetate content), and their blends (0.5, 1, 1.5, 2, 2.5, 3, and 5 parts/100 parts EVA) was investigated. An IR study showed some residual unsaturations retained in irradiated pure TMPTMA, while in blends all unsaturations were used up at a very early stage of irradiation. The concentration of the carbonyl group due to air oxidation increased in pure EVA and blends, but it reached a maximum at the 1.5-part TMPTMA level and 5-Mrad dose. Some ether linkages were formed during irradiation in pure EVA and the blends, although in pure EVA the concentration of ether linkages reached a maximum at the 2-Mrad dose and then decreased and in the blends it increased with an increase in radiation dose. Gel content showed an increasing trend with an increase in radiation dose, but it increased marginally with TMPTMA level. A blend of EVA with 1 part TMPTMA produced more gel than pure EVA at the same irradiation dose.