The effect of plasma-electron collision and their thermal motion is investigated on the externally injected electron in a warm magnetized plasma-filled cylindrical waveguide of cross section of 13.68 cm2. The numerical results are presented for the external electron-energy gain and its trajectory in a nonrelativistic γe=1 and stationary v0=0 warm magnetized plasma-filled waveguide. Results shows that for an electron-cyclotron frequency ωc greater than the electron-plasma frequency ωp, a 100 keV electron acquires a 1.74 MeV energy in a 2.5 cm distance for plasma density n0=1.08×1017/m3, magnetic field B0=0.193 T, microwave frequency f=7.64 GHz, plasma-electron thermal velocity vth=0.2c, and plasma-electron collision frequency ν=4 GHz, which is lower than the 7 MeV electron energy in a cold magnetized plasma-waveguide case. Space-charge effects and other nonlinear effects are assumed to be negligible in this model.