The electric properties of electron irradiated GaAs have been extensively studied by various authors [l, 21. In a recent study of the electron mobility profile of GaAs MESFETs it was reported that the contribution of the non-lattice scattering terms (ionized impurities and clusters) to the total free electron scattering probability increase after irradiation versus depth at distances d > 0.2 pm below the Schottky contact [3]. In the present note we report conductivity (c) and concentration (ND - NA) profiles up to 2 km below the surface on n-type GaAs layers before and after irradiation with 0.65 MeV electrons. Annealing results are also reported. We prepared on semi-insulating Cr-doped GaAs wafers VPE grown sulfur-doped n-type GaAs layers of two different thicknesses, i.e. 0.36 pm with free electron concentration 5 x 1OI6 cmW3a nd 5 vm with free electron concentration 2 x 1015 ~ m - S~ch.o ttky contacts of a Cr (70 nm)/Au (400 nm) layer were applied by vacuum evaporation. Electron irradiation at 0.65 MeV was carried out at room temperature. Low irradiation doses were chosen to prevent the formation of clusters. In Table 1 the characteristics and irradiation doses of the individual samples are given. The concentration ND - N, was obtained by differential capacitance measurements with 1 MHz small ac signal. The conductivity and concentration profiles were measured before and after irradiation.