In the present work the effect of copper oxide addition on the densification behavior and electrical conductivity of BaCe1-xGdxO3-delta (BCG) type ceramics is investigated. Small addition (1 mol%) of this sintering additive reduces both the calcination temperature (by similar to 250 degrees C and the sintering temperature (by -150 degrees C) and promotes at the same time the densification process. According to the X-ray diffraction analysis the BaCe1-xGdxO3-delta samples with 0 <= x <= 0.2 and the BaCe1-xGdxO3-delta samples with 0.0075 <= y <= 0.07 are single-phase. It was found that the samples with Cu, when sintered at 1450 degrees C for 3 h, have similar to 95% of relative density compared with pure BaCe1-xGd0.1CuyO3-delta samples that have similar to 86%. It was also found that the electrical conductivity of Cu-containing samples sintered at 1450 degrees C is comparable to those without Cu sintered at 1600 degrees C in oxidizing and reducing atmospheres. Cu-containing samples exhibit significantly higher conductivity in both air and hydrogen atmosphere. (c) 2007 Elsevier B.V. All rights reserved.