Two different preparative routes, one a wet chemical route (WCR) and the other a traditional solid state sintering route (SSR), have been used to synthesise the oxygen deficient perovskite BaZr0.5In0.5O3-delta. Analysis of X-ray powder diffraction data showed that both phases adopt cubic crystal structures. Environmental scanning electron microscope (ESEM) images showed that a smaller grain size was obtained for the WCR sample. Dynamic then-no-gravimetric analysis indicated significant mass losses for hydrated samples compared to their respective dried samples. Proton conductivity was investigated for hydrated and as-prepared phases under dry and wet atmospheres, respectively. The hydrated sample prepared via the solid state sintering route displayed a higher proton conductivity under dry conditions, reflecting the presence of fewer grain boundaries in this sample. (c) 2008 Elsevier B.V. All rights reserved.