This article deals with the degradation of solar cells induced by electron irradiation. We have exposed GaAs solar cells to different doses of accelerated electrons to create defects, which play an important role as non-radiative recombination centers. We try to achieve the same conditions to which the solar cells are exposed to in outer space. We have studied the variation of the photovoltaic characteristics of these cells versus electron flux. We found out that the open – circuit voltage of GaAs solar cells varies with the electron irradiation dose j, which we varied in the interval: 2x1012 elec.cm-2 < j <5x1015 elec.cm-2 and we found out that: Voc = 1.22 - 0.04 log j V Voc = 2.39 - 0.12 log j V for both, the diffusion and the recombination zones respectively. The density of the short-circuit current has been measured and we found that the current varies with the electron irradiation dose, according to the relation: Jsc = 62.47 - 3.45 log j mA.cm-2 The degradation of solar cells appears from the decrease of the maximum power when () increases.