The electrical conductivity of layered-perovskite-type La2Ti2O7 and Sr-doped La2Ti2O7 has been studied. La2Ti2O7 and (La0.9Sr0.1)(2)Ti2O7 with a layered-perovskite structure were successfully prepared by the Pechini process. The grain size of La2Ti2O7 was found to be 41, 57, and 70 nm for a firing temperature of 700, 1000, and 1300 degreesC, respectively. A single phase of (La0.9Sr0.1)(2)Ti2O7 was also obtained by firing at 1000 degreesC for only 2 h. The electrical conductivity of the layered compounds was measured as a function of partial oxygen pressures and temperatures by a complex impedance technique. La2Ti2O7 fired at 700 degreesC showed an ionic conductivity of 3.4 x 10(-6) S/cm at 700 degreesC, due to the Frenkel defects incorporated by low-temperature synthesis. As a result of the grain size refinement, the enhancement of electronic conductivity was also observed for La2Ti2O7. The ionic conductivity of (La0.9Sr0.1)(2)Ti2O7 was less than that of La2Ti2O7.