The formation of tricalcium phosphate (TCP) from dicalcium phosphate and calcium carbonate was investigated using differential thermal analysis (DTA), thermogravimetric analysis (TGA), and powder X-ray diffraction (XRD). DTA showed three distinct thermal events attributed to dehydration of dicalcium phosphate dihydrate (brushite, DCPD) to dicalcium phosphate anhydrous (monetite, DCPA), the formation of beta-calcium pyrophosphate (b-Ca2P2O7), and the calcination of calcium carbonate. TGA showed three weight losses corresponding to the three thermal events, respectively. XRD analysis showed that b-TCP formed, beginning at about 900°C, by the reaction of b-Ca2P2O7 with CaO and b-TCP changed to a-TCP above 1200℃. Further examination of the formation of TCP from calcium hydroxide (Ca(OH)2) and DCPA showed that b-TCP would form only after the decomposition of Ca(OH)2 to CaO and from the reaction of CaO with b-Ca2P2O7 at a fairly low temperature of 800℃. In addition, by naturally cooling a-TCP, formed at 1300℃ within the heating furnace, to room temperature, it was difficult to obtain a pure phase of b-TCP. The proposed mechanism of the reaction to form TCP may include the dehydration of brushite to monetite, dehydration of monetite to beta-calcium pyrophosphate, decomposition of calcium carbonate, the formation of b-TCP, and phase transition.