Nanocrystals of any drug are pure solid drug particles with a mean diameter in nanometer range. The aim of this study was to develop nanocrystals of a hydrophobic drug. carbamazepine, by addition of solvent to an antisolvent to achieve solubility enhancement. The developed nanocrystals were characterized for particle size, solubility, solid nanocrystals were characterized for DSC and XRD. These are considerable increase was found in the solubility of the nanocrystals as compared to pure drug. The nanocrystal development by antisolvent precipitation procedure using ethanol as solvent, water as antisolvent, it’s a very promising and effective method to increase the dissolution rate of carbamazepine.