By means of electrochemical vapor deposition (EVD), it is possible to grow thin, dense layers of zirconia/yttria/terbia solid solution (ZYT) on porous ceramic substrates. These layers can be used as ceramic membranes for oxygen separation. The kinetics of the EVD process, the morphology of the grown layers and their oxygen permeation properties are investigated. At a deposition temperature of 800 degrees C, the EVD layer growth is limited by bulk electrochemical transport. At 1000 degrees C the layer growth is limited by pore diffusion of the oxygen source reactant. The EVD-grown ZYT layers show columnar structures with prismatic grains on top; the size of the grains (1 to 2 mu m) increases slightly with temperature and deposition time. ZYT is deposited mainly in the cubic doped zirconia phase. Oxygen permeation experiments show that the oxygen permeation flux through the ZYT layers is limited by an electrochemical process. Permeation values in the order of 10(-8) mol/cm(2) s have been observed (900-1000 degrees C, air vs. CO/CO2).