Microwave synthesis of ceramics offers the advantage of efficient transformation of energy and heating throughout the volume efficiently in shorter period leading to fine crystallites. Hydroxyapatite (HA) and tricalcium phosphate (TCP) are widely used in the field of medicine and dentistry. Recently, biphasic calcium phosphate (BCP) ceramics has been paid attention as an ideal bone substitute due to its controlled degradability. In this paper, we report the in situ formation of BCP ceramic consisting of a mixture of HA and β-TCP in various ratios synthesized under microwave irradiation. The BCP powders were characterized by various techniques like DTA, TGA, XRD and FTIR. The thermal stability of the BCP powders was determined using differential thermal analyser and thermogravimetric analyser. The X-ray diffraction pattern of BCP powders shows the in situ formation of β-TCP in BCP powder. The amount of β-TCP phase increases as the Ca/P ratio decreases from 1.67 to 1.52. The Fourier transformed infrared spectroscopy analysis also confirmed the BCP formation. The in vitro solubility study of BCP powders in phosphate buffer of pH 7.2 showed the resorbable nature of the BCP ceramics. The present study demonstrates the feasibility of in situ formation of BCP ceramics using a domestic microwave oven. © 2001 Elsevier Science B.V. All rights reserved.