Induced noncolinear frequency doubling (INCFD) is presented as a new characterization technique for electro‐optic crystals. Using the interaction of two noncolinear laser beams for the generation of second harmonic light, the method yields a three‐dimensional spatial resolution. First experimental results of INCFD measurements on composition gradients in lithium niobate and on the spatial orientations of 90o‐domain walls in potassium niobate are shown. ©1996 American Institute of Physics.