We report on the visualization of domain wall strains in congruent LiNbO 3 using Bragg and Laue x-ray topography. The Laue geometry allows imaging through the entire crystal. Using monochromatic synchrotron undulator radiation and a magnifying x-ray camera, we are able to image domains created by electric field poling, as well as the strain associated with the subsequent application of an electric field to the domains in real time. Electric fields below the coercive field applied along the c-axis produce unexpected and complex strain patterns which are precursors to 180° domain wall switching. The strains observed with field off and on in the Laue topographs differ significantly from the surface strains observed previously with Bragg topography.