Polymer insulators for electric apparatus and high-voltage overhead lines are promising for replacing porcelain and glass insulators. The possibility of this application is shown by radiation-chemical technology for the manufacture of rod-shaped polymer insulators. An ethylene and vinyl acetate copolymer (EVA) was used as the basis for polymer insulators. The composition also contains aluminium hydro;dde as a filler and N,N’-m-phenylene dimaleimide as a sensitizer. The investigation of gamma-radiation-induced crosslinking of this composition made it possible to establish the following optimum conditions of radiation processing of insulators : the absorbed dose of up to 200 kGy at a dose rate of 10 kGy/h in air. By forming a three-dimensional network in the polymer bulk by radiation, the service properties of the insulators are improved : Shape and heat stability is >200 degrees C and the stability to tracking and erosion >200 h. Differential scanning calorimetry (DSC) and a method of stress relaxation were used in evaluation. In the Saint Petersburg region (Russia), several types of high-voltage (10-110 kV) polymer insulators are manufactured with the application of such radiation-chemical technology.