Single crystals of L-histidinium bromide (L-HBr), a semi organic nonlinear optical (NLO) material have been successfully grown by the temperature lowering and evaporation methods. The solubility of the material was measured in various solvents such as ethanol, acetone and water. It was found to have extremely low solubility in ethanol and acetone. Therefore good quality crystals of L-HBr were successfully grown from aqueous solution by the temperature lowering method. Large size single crystals of L-HBr were grown with dimension 30 x 20 x 8 mm(3) in 30 days. The grown crystals were characterized by recording the powder diffraction and identifying the diffracting planes. Using single crystal diffractometer the morphology of L-HBr crystal was identified. Optical transmission spectra revealed the optical properties of the grown crystals. The NLO property of the crystal was confirmed by Kurtz SHG test and compared with NLO of KDP crystals. Microhardness studies carried out on different planes show anisotropy in the hardness behavior. (C) 2003 Elsevier B.V. All rights reserved.