BaZr 1-x M x O 3-d (M=Ce and/or Y) perovskite materials are good potential candidates for Protonic Ceramic Fuel Cell (PCFC) electrolyte due to their remarkable property of protonic conduction at intermediate temperature (400-600°C). Fabbri et al. have reported a protonic conductivity of 2.10-2 S.cm-1 at 600°C for BaCe 0.7 Zr 0.1 Y 0.2 O 3-d [1]. However, the synthesis of these materials requires high temperature (1500°C) by solid state reaction. The hydrothermal synthesis in supercritical water appears then as a way to synthetize perovskite materials at a temperature as low as 400°C. Furthermore, this process allows the formation of nanometric powder. Finally the continuous hydrothermal process offers many advantages such as: "soft-chemistry" route, low cost and sustainable elaboration.