The effect of Mn site doping by small amount Ru (5 %) on the transport and magneto-transport properties of the Ln0.67Sr0.33Mn1−x Ru x O3 (where Ln = La, Pr, and Nd, x = 0, 0.05) has been studied. Polycrystalline samples were synthesized by the conventional solid state reaction method. The samples of Pr0.67Sr0.33Mn1−x Ru x O3 and Nd0.67Sr0.33Mn1−x Ru x O3 have shown single phase with orthorhombic structure as well as La0.67Sr0.33Mn1−x Ru x O3 has rhombohedral are revealed from XRD measurement. The temperature dependence of the resistivity is measured from 5 to 400 K. La0.67Sr0.33Mn0.95Ru0.05O3 shows the metal–insulator (M–I) transition at 379 K while Pr0.67Sr0.33Mn0.95Ru0.05O3 and Nd0.67Sr0.33Mn0.95Ru0.05O3 have shown M–I transition at 294 and 249 K, respectively. The magnetoresistance (MR) was measured with an applied magnetic field of 1, 3 and 5 T. Though the M–I transition temperature decreases marginally, MR up to 70 % has been observed.