Sr- and Mn-doped LaGaO(3) (La(0.8)Sr(0.2)Ga(0.5)Mn(0.5)O(3-delta), LSGMn) has been synthesized using a glycine nitrate combustion method. Powder X-ray diffraction examinations show that the synthesized LSGMn has a pure single cubic perovskite phase. Four-probe direct current conductivity characterization indicates that the conductivity of the sintered LSGMn in wet H(2) is lower than that in air, whereas the activation energy in wet H(2) is higher than that in air. Such an expected p-type conduction mechanism is the result of the valence change of Mn, which enables LSGMn to be a mixed ionic and electronic conductor. Using LSGMn as an anode and LSCF as a cathode, the peak power density at 800 degrees C of the LSGM electrolyte supported all-perovskite cells can reach 460 mW/cm2 using wet H(2) as fuel and ambient air as an oxidant. Further, LSGMn anode has showed reasonable sulfur tolerance in H(2)-containing 100 ppm H(2)S and the all-perovskite cell has demonstrated good performance stability in the short-term operation at a constant cell voltage of 0.7 V.