The synthesis, conductivity properties, area specific resistance (ASR) and thermal expansion behaviour of the layered perovskite SmBaCo 2 O 5+d (SBCO) are investigated for use as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The SBCO is prepared and shows the expected orthorhombic pattern. The electrical conductivity of SBCO exhibits a metal–insulator transition at about 200°C. The maximum conductivity is 570Scm −1 at 200°C and its value is higher than 170Scm −1 over the whole temperature range investigated. Under variable oxygen partial pressure SBCO is found to be a p-type conductor. The ASR of a composite cathode (50wt% SBCO and 50wt% Ce 0.9 Gd 0.1 O 2−d , SBCO:50) on a Ce 0.9 Gd 0.1 O 2−d (CGO91) electrolyte is 0.05Ωcm 2 at 700°C. An abrupt increase in thermal expansion is observed in the vicinity of 320°C and is ascribed to the generation of oxygen vacancies. The coefficients of thermal expansion (CTE) of SBCO is 19.7 and 20.0×10 −6 K −1 at 600 and 700°C, respectively. By contrast, CTE values for SBCO:50 are 12.3, 12.5 and 12.7×10 −6 K −1 at 500, 600 and 700°C, that is, very similar to the value of the CGO91 electrolyte.