[en] A theoretical model is put forward that elucidates the space charge formation in MOS transistors under gamma irradiation. The threshold potential shift ΔU,sub,(T) due to the space charge formation is proportional to the applied potential U,sub,(G) at low U,sub,(G) and to the Sio₂ layer thickness squared at high U,sub,(G). The theoretical speculations have been checked and proved experimentally with czechoslovakian MN2009 type transistors gamma-irradiated using ¹³⁷Cs and ⁶⁰Co sources. At the 10³ rad dose ΔU,sub,(T) = 80 mV. The marginal sensitivity at high U,sub,(G) amounted to 9.8x10^-3 μV/rad. The model developed may account for the most of phenomena observed including fading and tempering of the space charge