The manufacture of high-surface area, un-agglomerated nano-sized (1-100 nm) bioceramic particles are of interest for many applications including injectable/controlled setting bone cements, high strength porous/non-porous synthetic bone grafts, and the reinforcing phase in nano-composites that attempt to mimic the complex structure and superior mechanical properties of bone. In the present study, we report on the manufacture of nano-particle hydroxyapatite powders by several wet chemical methods, which incorporate a freeze-drying step. In particular, it was found that the emulsion-based syntheses yielded powders with high surface areas and small primary particle sizes. Freeze drying rather than oven drying of powders prepared by conventional wet chemical synthesis yielded a nano-sized powder with a comparatively higher surface area of 113m2/g. All powders were calcined in air in a furnace at 900°C investigate the effects of synthesis method on phase purity and surface area. The materials were characterized by a range of analytical methods including Fourier-transform infrared spectroscopy employing the photo acoustic (PAS-FTIR) sampling technique, BET surface area analysis, X-ray powder diffraction (XRD), and the particles were examined using a transmission electron microscope (TEM). © 2003 Kluwer Academic Publishers.