The synthesis of bulk nanometric La0.9Sr0.1Ga0.8Mg0.2O3 - delta (LSGM) was investigated using the high-pressure spark plasma sintering (HP-SPS) method. The starting precursor nanopowders were synthesized by the Pechini method. Single phase, fully dense LSGM was obtained with a sintering cycle of 5 min under a uniaxial pressure of 700 MPa at sintering temperatures as low as 850 degrees C. This sintering temperature is several hundred degrees lower than those typically reported for LSGM materials. A considerable reduction in the final grain size of the sintered materials was consequently observed. Fully dense samples with an average grain size as low as 65 nm could be prepared by this method. Despite the short. low temperature sintering process a single phase material was obtained. Due to the small size of the constituting grains it was possible to estimate the specific grain boundary conductivity by impedance measurements. (C) 2008 Elsevier B.V. All rights reserved.