We report on the structure, magnetism, and transport properties of composites La2/3Sr1/3MnO3/SrTiO3 synthesized at 700 °C for 10 min. The results show that high-field magnetoresistance is almost the same for all composites. However, an enhancement of the low-field magnetoresistance is observed due to the weakening of the magnetic correlations with decreasing the La2/3Sr1/3MnO3 component of the composite. This paper suggests that the weakening of magnetic coupling between the nanostructured grains or films is a viable route to achieve a large magnetoresistance at low applied magnetic fields.