ABSTRACT In the present work, hydroxyapatite (HAp) was successfully synthesized by wet precipitation method using Ca(NO3)2.4H2O, and (NH4)2HPO4, and NH4OH as starting materials. The precipitate was dried by using freezer drier for 3 days and then calcined at 8000C for 1 hour. The powder sample was characterized by scanning electron microscopy (SEM), wide angle x-ray scattering (WAXS), IR and particle size analyzer. As a result, the HAp particle exhibited a micrometer-sized rod shape with a dimension of 0.55-1.2 àm in diameter and 2.3-2.9 àm in length, and the crystallinity increased after calcinations for Ca/P ratio of1.66. Keywords: Hydroxyapatite; precipitation; crystallinity; bioceramic