Abstract: Hydroxyapatite (HA) or MWNT/HA was synthesized by reacting Ca(NO3)2·4H2O with (NH4)2HPO4 with the help of ultrasonic agitation in the absence or presence of MWNTs, and the resulting HA and MWNT/HA were characterized by IR, XRD and TEM. Results indicated that HA samples were almost completely composed of nano-sized spindle-like HA crystals, which were all of the same crystal phase and high crystallinity without agglomeration. Under optimized reaction parameters for HA crystals, the MWNTs were well dispersed in the HA matrix and some HA even deposited onto the MWNT surfaces and coated them, indicating a good compatibility between HA and MWNTs.