Octacalcium phosphate (OCP) and adipic acid-intercalated complexed OCP (Adi-OCP) were synthesized. Moreover, we made ceramic bodies out of them through a hydrothermal hot-pressing (HHP) method. Characteristic features of both the powder and ceramics were investigated by the X-ray diffraction method (XRD). Surface morphology of the ceramics was observed by scanning electron microscopy (SEM). Density, compressive strength and pore size distribution of the ceramics were measured. Crystalline structure of the newly developed OCP ceramics had no phase transformation from the starting materials. Moreover, the newly developed OCP ceramics had good mechanical properties only through the HHP treatment with a temperature as low as 110 degrees C. In order to evaluate bioactivity, the ceramics were immersed in simulating body fluid (SBF). It was predicted that OCP and Adi-OCP had better bioactivity than that of conventional HAp ceramics. (C) 2009 Elsevier B.V. All rights reserved.