The effect of the addition of potassium chloride (KCl) in bulk growth unidirectional (0 0 1) potassium dihydrogen phosphate (KDP) grown from aqueous solution by Sankaranarayanan-Ramasamy (SR) method has been studied. The crystal of 15 mm diameter, 95 mm height was grown by SR method. Addition of 5 M% KCl in the bulk growth medium increases the quality as well as the growth rate. The grown crystals were characterized by UV-Vis spectroscopy, microhardness and dielectric studies. It reveals that the SR method grown crystalline quality and perfection is better than the conventional method grown crystal. (C) 2008 Elsevier B.V. All rights reserved.