Homogeneous fine grained La-2(Zr,Y)(2)O-7 /LaCoO3-delta-based composite materials were obtained from simple mixture of the components and solid state reaction between LaCoO3-delta and yttria-stabilized zirconia. Thermal expansion data can be fitted to simple mixture rules to predict the composite behavior from the properties of the individual components. The dependence of total and ionic conductivity on the volume fraction of the conductive phase can be described by the General Effective Media equation. The resistance to thermal cycling was evaluated and found satisfactory (C) 2001 Elsevier Science BN. All rights reserved.