The inverse emulsion copolymerization of (2-methacryloyloxyethyl)trimethylammonium chloride with acrylamide using gamma rays has been studied. Aqueous monomer solutions were emulsified in kerosene with a blend of two surfactants (Span80 and OP10). The gel effect is evident from the increase of the molecular weight with conversion and also from the percentage conversion versus irradiation time curves. The effects of dose rate, concentration and composition of the monomer, emulsifier content, temperature, etc. on the polymerization conversion and the intrinsic viscosity of the polymer have been examined. The polymer molecular weight increases with decreasing dose rate and increasing monomer concentration. These results are discussed in connection with the mechanism of inverse emulsion polymerization.