Fatigue of piezoelectric properties was investigated at the grain scale using piezoresponse force microscopy in 0.7Pb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) (PMN-PT) thin films grown on platinum and LaNiO3 electrodes. Single grains were fatigued then electromechanical activity was probed by the nanoscale probe tip of the atomic force microscope. Local fatigue phenomenon with switching cycles is observed whatever the metallic or oxide bottom electrode nature. However, better fatigue resistance is clearly evidenced when the ferroelectric layer is deposited on oxide electrode. Fatigue effect starts at 10(8) switching cycles for grains grown on platinum while 4x 10(8) on LaNiO3. Such improvement of fatigue endurance is mainly attributed to the oxide nature of the LaNiO3 electrode, which acts as an oxygen source for the film during fatigue process. Effect of electrode nature on piezoelectric fatigue in such 70/30 PMN-PT ferroelectric films is evidenced at the nanometer scale level. (C) 2011 Elsevier B.V. All rights reserved.