The La0.6Pb0.4MnO3(LPMO) thin films wereinsitudeposited at different oxygen partial pressure and at a substrate temperature of 630 °C by pulsed laser deposition. The films grown at lower oxygen partial pressures showed an increase in lattice parameter and resistivity and a decrease in the insulator–metal transition temperature as compared to the stoichiometric LPMO thin film grown at 400 mTorr. Further, these oxygen‐deficient thin films showed over 70% giant magnetoresistance (GMR) near the insulator–metal transition temperature against the 40% GMR in the case of stoichiometric thin films. ©1995 American Institute of Physics.