We have investigated the influence of chromium (Cr) doping on the magneto-electrical properties of polycrystalline samples La_0.75Sr_0.25Mn_1−xCr_xO₃ (0.15 ≤ x ≤ 0.25), prepared by the sol–gel method. Comparison of experimental data with the theoretical models shows that in the metal-ferromagnetic region, the electrical behavior of the three samples is quite well described by a theory based on electron–electron, electron–phonon and electron–magnon scattering and Kondo-like spin dependent scattering. For the high temperature paramagnetic insulating regime, the adiabatic small polaron hopping (SPH) model is found to fit well the experimental curves.