A basic study of the differences in elastic properties between single- and multi-domain crystals ofLiTaO3is conducted by measuring the longitudinal velocities forX-,Y-, andZ-cut specimens and the shear velocities forZ-cut specimens. Two sets ofX-,Y-, andZ-cut specimens are prepared: one is for normal (single-domain) specimens and the other is for perfectly depoled (multi-domain) specimens. For the longitudinal wave propagation directions along theYandZaxes, the velocities for the single-domain specimens, due to piezoelectricity, are 91.5 m/s (1.59&percent;) and 92.7 m/s (1.50&percent;) larger than those for the multi-domain specimens, respectively. On the other hand, for theX-axis longitudinal andZ-axis shear wave propagation directions, piezoelectricity is uncoupled, but the very interesting velocity changes are that the longitudinal and shear velocities for the single-domain specimens are 48.4 m/s (0.87&percent;) and 135.6 m/s (3.79&percent;) smaller than those for the multi-domain specimens, respectively. These differences are introduced by the poling operation for multi-domainLiTaO3crystals. Four elastic constants ofc11,c33,c44,andc14in the multi-domain state are determined. ©1997 American Institute of Physics.