Abstract The paper deals with experimental results on space charge accumulation and relaxation in dielectrics irradiated with fast electrons. The results were mainly obtained by using methods of radiation diagnostics of electric potentials. The samples were irradiated in shorted geometry, i.e. electrodes were applied to the surfaces and grounded. The dynamics of a space charge in a volume uniform and non-uniform electon irradiation was investigated. The results are in a good agreement with the conclusions of the phenomenological model of space charge storage at uniform charging. The electrophysical parameters of dielectrics responsible for space charge storage, namely radiation-induced conductivity, effective mobilities of negative and positive carriers, their dependence upon the temperature and the absorbed dose rate were defined. The effects of space charge layering and influence of sample thickness on the space charge relaxation take place with non-uniform charging. The paper gives the experimental data for polymers: polymethylmethacrylate (PMMA) polyethylene (PE), polystyrene (PS), ionic crystals of LiF and glasses.