Using a low-resolution electron-impact spectrometer in excitation function mode, the energy dependence of differential cross sections for elastic scattering of electrons on argon and krypton was studied. Relative cross sections were put on an absolute scale by normalizing to the previous data of Srivastava et al at one conveniently chosen energy and angle in each gas. Differential cross sections for elastic scattering of electrons on krypton are compared with previously published cross sections for positron scattering. No broad resonance-like structures are observed in the case of electron scattering but the energy dependence, especially in krypton, shows a strong variation with energy which is not observed for positrons.