Single-phase La 0.7 Sn 0.3 MnO 3 (LSnMO) thin films were fabricated on SrTiO 3 (STO) substrates by pulsed laser deposition (PLD). The as-deposited films, though were insulating with no sign of insulator-–metal transition (IMT), did display paramagnetic–ferromagnetic transition (PFT) around 150K. Ex situ annealing of the films at 850°C in 250Torr oxygen for 4h, nonetheless, not only significantly improves the crystallographic quality but also raises IMT and PFT at 315K and 320K, respectively. The manifestations of spin-glass-like behavior in both the as-deposited and post-annealed films suggest that it could be intrinsic LSnMO, albeit transport properties can be drastically changed by the strain originating from large ion-size misfit between Sn and La and film/substrate epitaxial relation. The preliminary X-ray absorption spectroscopy shows signature of Mn 3+ /Mn 2+ mixed-valence indicating that tetravalent Sn ions does result in electron-doping into the eg band of Mn.