A polymeric sol–gel combustion method has been used to synthesize nanocrystalline hydroxyapatite (HA) powder from calcium nitrate and triethyl phosphate with the addition of NH₄OH. The sol–gel combustion process generates phase-pure nanocrystalline HA powder, as characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Sintering of the HA powder compact at 1200°C for 2 h leads to a 93% theoretical dense ceramic body. This method offers an easy route for the preparation of phase-pure nanocrystalline HA powder.