Using the stimulated body fluid (SBF) as solvent, nano-sized single-crystalline HAp fibers have been synthesized in SBF solution at 37 degrees C without adjusting the pH values during the whole reaction time. The synthesized HAp fibers have a length ranging from 60 nm to 100 nm, a uniform diameter of 3-5 nm. Characterization by high-resolution transmission electron microscopy (HRTEM) shows that the synthesized HAp fibers grow along [0 0 1] or [0 10], and there exist structural defects in the synthesized HAp nanofibers. the thermal gravity analysis (TG) and corresponding X-ray powder diffraction (XRD) analysis indicate that the heat treatment temperature for HAp fibers should not be above 700 degrees C. The HAp fibers with length and diameter in the range of nano-size could be an ideal structure as a specific reinforcement in the biomaterials for bone tissue implantation. (c) 2005 Elsevier B.V All rights reserved.