Potassium dihydrogen phosphate is a well-known non-linear optical material and has immense uses in solid state laser source devices. In the search for suitable materials with higher non-linear responses and good optical, thermal, mechanical properties as well as fast growth rate, an attempt has been made to grow potassium dihydrogen phosphate separately doped with urea and KCl in different molar ratios. The effect of impurities on the growth, nucleation kinetics, surface morphology, structural, optical and mechanical properties have been investigated. With increasing impurity concentration (viz. 1-10 mol%) the growth rate was found to increase. Vicker' s microhardness study shows higher mechanical stability ill urea doped KDP crystals than KCl. Moreover, the addition of KCl improves the quality of the Crystal Surface and yields highly transparent crystals with well defined features. (C) 2002 Elsevier Science B.V. All rights reserved.