Hydroxyapatite (Ca10 (PO4)6 (OH) 2: HAp) is the principle inorganic constituent in bone and hence widely used ceramic biomaterials. To effectively control the processing parameters several investigations have been made. With such a wide variety of methods for the synthesis of HAp nanoparticles, choosing a definite procedure to synthesize a well distinct powder can be difficult. In general, it is suitable to control the crystal size of materials using surfactant aided routes. Hence, in our present investigation we try to synthesis HAp crystals using surfactant aided method. The effect on morphology of HAp using a cationic surfactant cetyl trimethyl ammonium bromide (CTAB) by hydrothermal reactions is discussed. These crystals were characterized for crystallinity, stoichiometric ratio, and crystalline size.