Experimental results on the heating of electrons by large amplitude electrostatic shocks, which were generated by counterstreaming plasmas, are described. The heating was studied in both two cases of plane and hemispherical shocks. The temperature observed behind the shock front was found to reach about five times of the initial one in the plane case and about thirty times in the hemispherical case. Comments on the isothermal model of electrons, which has been often used so far, are also given.