We describe the generation of terahertz radiation by optical rectification in an electro‐optic crystal mosaic. The mosaic is constructed from four single crystals of the organic salt dimethyl amino 4‐N‐methylstilbazolium tosylate and is approximately 1 cm2in area. We characterize both the optical rectification efficiency and the spatial and temporal profiles of the generated terahertz beam, and find that the mosaic performs as well as a single crystal. ©1995 American Institute of Physics.