Gamma irradiation has been used as an alternative way of curing diol-diisocyanate by means of specific catalysts and/or elevated temperatures. A mixture of toluene diisocyanate (TDI) and hydroxy terminated polybutadiene (HTPB) oligomer were irradiated over a dose range of 0–720 kGy using a 5 kCi60Co -source. Various compositions were formulated and also suitable additives were incorporated. Disappearance of the isocyanate peak in the IR spectra was considered as a measure of its consumption. The conversion characteristics showed a profound influence of irradiation. A suitable mechanism is envisaged.