In order to obtain the properties of the sintered as-dried calcium phosphate with [Ca]/[P] = 1.50, the characteristics of sintered pellets have been investigated using X-ray diffraction (XRD), inductively coupled plasma-mass spectrometry (ICP-MS), Fourier-transform infrared (FT-IR) spectra, Vickers hardness indentation and scanning electron microscopy (SEM). When the pellet samples were sintered between 700 degrees C and 1200 degrees C for 4 h, the hydroxyapatite (Ca-10(PO4)(6)(OH)(2), HA) still maintained the major phase, accompanied with the rhenanite (NaCaPO4) as the secondary phase and beta-tricalcium phosphate (beta-Ca-3(PO4)(2), beta-TCP) as the minor phases. In addition, the HA partially transformed to alpha-tricalcium phosphate (alpha-Ca-3(PO4)(2), alpha-TCP) and tetracalcium phosphate (Ca-4(PO4)(2)O, TTCP), when the pellet samples were sintered at 1300 degrees C and 1400 degrees C, respectively, for 4 h. The maximum density and Vickers Hardness (HV) of sintered pellet samples were 2.85 g/cm(3) (90.18% theoretical density (T. D.)) and 407, which appeared at 1200 degrees C and 900 degrees C, respectively.