The influence of electron-ion collisions in plasma on the electron energy gain and total energy of an externally injected electron inside an elliptical waveguide, including collisional plasma using the transverse electric mode, is investigated. It is noted that microwave radiation is used for excitations of the TE 11 even mode in the configuration. The electromagnetic field components of the TE 11  mode in the considered waveguide are obtained and graphically presented. It is seen that the strength of the fields reduces in the collisional plasma. Furthermore, the deflection angle, energy gain of the electron and total energy of the electron due to the mode are obtained. It is illustrated that electron-ion collisions in plasma reduce the energy gain and total energy of electrons injected into the elliptical waveguide.