A novel technique to synthesize hydroxyapatite (HAP) with nanocrystalline structure was developed in this study. Nanocrystalline HAP was prepared by a precipitation method with aid of ultrasonic atomization using Ca(NO3)2 x 4H2O and (NH4)2HPO4 as raw materials. The crystallization and the morphology of the prepared nanopowder were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The obtained powder was 30-40 nm in size and homogenous. The effect of some surfactants on the crystallization and morphology of HAP nanoparticles was also investigated. The results showed that the synthesis method used in this study can effectively shorten the reaction time while improving the homogeneity of the powder when compared to other published methods. It was also found that the addition of a small amount of surfactant glycine during the precipitation synthesis can reduce the agglomeration of the HAP nanoparticles.