The transport properties of members of the solid solution (100 - x)CeO2 center dot xLa(0.6)Sr(0.4)CoO(3) (CexLSC), where x=5, 7.6, and 10.6 mol% have been investigated under oxidising and mildly reduce atmospheres. The single phase solid solutions CexLSC have fluorite-type structure (space group Fm (3) over barm) with Ce replaced by La. Sr, and Co. The unit cell volume expands with increasing degree of substitution. The CexLSC compositions exhibit thermally activated conductivity behaviour over a temperature range of 150-900 degrees C. The bulk conductivity increases up to 5-6 orders of magnitudes. In contrast to the undoped CeO2, the grain boundary conductivity determines the transport properties of the CexLSC solid solutions only below 200 degrees C. The total conductivity of the CexLSC compositions with x > 5 mol% seems to be enhanced due to the increase in the concentration of oxygen vacancies and the emergence of the hole charge carriers. Results obtained in the present study demonstrate that the fabrication method does not greatly influence the transport properties of the CexLSC solid solutions. (C) 2010 Elsevier B.V. All rights reserved.