The phase evolution and electrical conductivity of undoped and calcium-doped GdAlO3 samples have been investigated. The undoped and doped compositions of GdAlO3 were prepared through citrate gel process. Analysis of the phases was carried out using X-ray diffraction (XRD). The microstructural evaluation of the samples was carried out by SEM/EDS. The electrical conductivity of Gd1-xCaxAlO3-delta (x = 0-0.3) was measured using ac impedance spectroscopy as a function of temperature ranging from 300 to 1000 degrees C under air. Among the doped compositions, Gd0.85Ca0.15AlO3-delta exhibited a conductivity of 0.057 S/cm at 1000 degrees C. (C) 2005 Elsevier Ltd. All rights reserved.