The ionic conductivity of composite solid electrolytes (1-x)CsHSO4-xTiO(2) (x = 0-0.7) has been investigated. The low-temperature conductivity of the composites was shown to exceed by more than two orders of magnitude that of pure CsHSO4. The conductivity enhancement depends on the dispersoid concentration and its specific surface area. This effect is caused by the strong interface interaction between CsHSO4 and TiO2 in composites.