Magnetoresistive properties of Gd doped various polycrystalline samples of Ruddlesden -Popper series (La1-xSrx)n+1MnnO3n+1 (n = 2) sintered at temperature 11000C for 24 hours in air have been investigated from room temperature down to liquid nitrogen temperature using standard four-probe technique. X-ray diffraction pattern have confirmed the single phase structure of all the samples with no significant trace of impurity. Sample La1.4Sr1.6Mn2O7 shows a Metal-Insulator (M-I) transition with a peak in the electrical resistivity at temperature Tp ~ 134K and 117 K with an applied magnetic field of 0.86 and O Tesla, respectively. Replacement of La by small amount of Gd atoms in this compound is found to lower the ferromagnetic (or metal-insulator) transition temperature, an effect which would be due to bond bending caused by the lattice adjusting to the size differential between the La and Gd ions. On the contrary, normalized resistivity behavior as a function of temperature for samples La1.0Gd0.4 Sr1.6Mn2O7, La1.0Gd0.6Sr1.4Mn2O7, and La1.0Gd0.8Sr1.2Mn2O7 in zero field and in an applied magnetic field of 0.86 T reveal that when non-magnetic Sr is replaced with magnetic Gd atom the transition temperature increases dramatically favoring metallic phase. The magnetic property of Gd atom might be responsible for higher transition temperature. Increase in magnetoresistance at lower field is observed to be faster than at higher field. For example, sample of La1.4Sr1.6 Mn2O7 exhibited 15% magnetoresistance (MR) at an applied magnetic field of 0.13 T whereas the MR of 19% has been obtained for this sample upon the application of 0.86 T magnetic field. All the other compounds exhibited similar behavior. The exhibited large MR effects in this compound at low temperature and very low field might be associated with magnetic-domain based scattering or spin-polarized tunneling between grains.