Porous samples of composition of BaZr0.93Y0.07O3-delta were fabricated. Electrical conductivity of porous samples was measured using a 4-probe dc method over a p(O2) range from 7.3 x 10(-6) to 1 atm and over a temperature range from 500 to 800 degrees C. The results showed that the electrical conductivity increases with increasing p(O2), a characteristic of electron-hole conduction. Above p(O2) of 0.01 atm, the measured total conductivity was fitted to sigma(t) = sigma(i) + fp(O2)(1/4) where sigma(i) is the ionic conductivity and fp(O2)(1/4) is the electronic (hole) conductivity. The activation energies were estimated to be similar to 0.57 +/- 0.15 and similar to 1.01 +/- 0.04 eV for oxygen ion and electron-hole conduction, respectively. The oxygen ion transference number ranged between similar to 0.01 and 0.7 over the p(O2), and the temperature ranges investigated. Electrical conductivity measurements were also carried out in H2O-containing atmospheres. It was observed that at a temperature below similar to 550 degrees C, the predominant ionic conduction was due to protons. (c) 2004 Elsevier B.V. All rights reserved.