The effect of redox cycles on the reducibility, structural, and electrical properties of dense pellets of ceria-zirconia solid solutions has been investigated by temperature programmed reduction studies, X-ray diffraction technique, Raman spectroscopy, and electrochemical impedance spectroscopy. Similarities and differences among the compositions with high (Ce0.80Zr0.20O2), intermediate (Ce0.50Zr0.50O2), and low (Ce0.20Zr0.80O2) amounts of ceria were evaluated in view of their application as active components for solid oxide fuel cell (SOFC) anodes. Cycles of reduction and reoxidation, respectively, at 1273 and 873 K, promote the reduction of all the compositions investigated, shifting it at a lower temperature. Moreover, redox treatments cause a significant change in the crystal structure of Ce0.50Zr0.50O2, ultimately leading to the formation of cubic pyrochlore phases as the reduction temperature increases. The correlations among structural changes, redox, and electrical properties of these materials are discussed. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3518756] All rights reserved.