Electric field-induced changes in shapes of smectic-A domains in an isotropic phase has been observed in the binary mixture of octyloxycyanobiphenyl with dodecyl alcohol. It is found that the average size of hemispherical smectic-A domains on substrate surfaces is decreased with increasing electric field. These experimental results can be explained by the electric-field induced spontaneous curvature. ©2000 American Institute of Physics.