Composites of Strontium- and Magnesium-doped lanthanum gallate, La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM), and yttria-stabilized zirconia, Zr0.9Y0.1O1.95 (YSZ), with weight ratios of 9.5:0.5, 9:1 and 8.5:1.5 were first prepared by co-precipitation route. The component compounds, LSGM and YSZ were also prepared by the same route for comparative study. X-ray Rietveld analyses revealed that the sintered LSGM-YSZ composites contain mainly perovskite orthorhombic LSGM phase along with fluorite YSZ phase similar to that of the cubic zirconia. Scanning Electron Microscopic image of the composite depicted the spherical- and oval-shaped grains. XPS spectra of the composite exhibited the LSGM along with a trace amount of the YSZ constituents. Electrical conductivity of the three systems was measured in the frequency range 20 Hz-1 MHz and in the temperature range of 400-700 A degrees C. LSGM-YSZ composite electrolyte with 9:1 ratio was found to exhibit enhanced electrical conductivity in comparison to LSGM and YSZ systems. Moreover, it exhibited lower activation energy than that of their individual components.