Ba and Sr beta-alumina ionic conductors were synthesized by solid state sintering at 2033 to 2073 K and their electrical conductivities were measured by a.c. impedance spectroscopy. The electrical conductivities at 1673 K were 2.05 x 10(-2) and 4.6 x 10(-3) S m(-1) for Sr and Ba beta-aluminas, respectively. An oxygen concentration cell and d.c. polarization methods were applied to measure the ionic transference numbers. The values obtained by the two methods were almost in agreement at more than 1400 and 1673 K for Sr beta-alumina and Ba beta-alumina, respectively. Sr beta-alumina could have slightly greater ionic transference numbers than Ba beta-alumina.