Unidirectional (1 0 1) potassium dihydrogen orthophosphate (KDP) single crystal was grown for the first time by Sankaranarayanan-Ramasamy (SR) method. The (1 0 1) oriented plate was mounted as seed at the bottom of the glass ampoule and the crystal of 30 mm diameter, 55 mm height was grown. The grown crystals were characterized by UV-vis spectroscopy, microhardness, dielectric and etching studies. The SR method grown KDP has higher transmittance compared to conventional method grown crystals. The crystals grown by SR method have much higher hardness value than conventional method grown crystals. The dielectric constant was higher and the dielectric loss was less in SR method grown crystal as against conventional method grown crystal. Dislocation density is less in SR method grown KDP compared to conventional method grown KDR (C) 2008 Elsevier B.V. All rights reserved.