Porous samples of composition of BaZr 0.93 Y 0.07 O 3−δ were fabricated. Electrical conductivity of porous samples was measured using a 4-probe dc method over a pO2 range from 7.3×10 −6 to 1atm and over a temperature range from 500 to 800°C. The results showed that the electrical conductivity increases with increasing pO2, a characteristic of electron–hole conduction. Above pO2 of 0.01atm, the measured total conductivity was fitted to σt=σi+fpO21/4, where σ i is the ionic conductivity and fpO21/4 is the electronic (hole) conductivity. The activation energies were estimated to be ∼0.57±0.15 and ∼1.01±0.04eV for oxygen ion and electron–hole conduction, respectively. The oxygen ion transference number ranged between ∼0.01 and 0.7 over the pO2 and the temperature ranges investigated. Electrical conductivity measurements were also carried out in H 2 O-containing atmospheres. It was observed that at a temperature below ∼550°C, the predominant ionic conduction was due to protons.