Solid oxide fuel cell (SOFC) electrolytes are currently manufactured from yttria stabilised zirconia. A limitation of this material is the high operating temperatures needed for efficient operation, approximately 1000C, as this can lead to sealing problems and require expensive nickel/chromium alloy auxiliary components. Alternative electrolytes, which allow operation at reduced temperatures, such as gadolinium doped cerium oxide have been suggested. However these ceramic materials often exhibit inferior mechanical properties. In this paper the manufacture and characterisation of composite electrolytes consisting of 3% yttria stabilised zirconia particles in a 20% gadolinia doped ceria matrix is described. Results suggest improvements in strength can be achieved by the composite approach.