Abstract Cerium zirconate, Ce2Zr2O8(s), is an interesting material having potential applications such as matrix for immobilization of nuclear waste, component in the inert matrix fuel, oxygen storage capacitor and catalyst for chemical reactions, etc. Long term stability of the compound under reactive conditions is essential for its utilization. Thermodynamics plays an important role in predicting the stability of the material. The present paper describes determination of the standard molar enthalpy of formation (ΔfH°298) of Ce2Zr2O8(s) employing a high temperature solution calorimeter. The enthalpies of dissolution of CeO2(s), ZrO2(s), Ce2Zr2O8(s) in liquid Na2O+MoO3 solvent (3:4M ratios) at 986K were measured employing a Calvet Calorimeter. The standard molar enthalpy of formation of the compound at 298K (ΔfH°298) was calculated by combining the experimentally determined values of the reaction enthalpies with the auxiliary data from the literature. The standard enthalpy of formation (ΔfH°298) of Ce2Zr2O8 was found to be –(4344.0±4.0) kJmol−1. Ce2Zr2O8(s) is a metastable compound, which decomposes to Ce-rich ZrO2 and Zr-rich CeO2 fluorite-type phases, when heated above 1673K. The extent of metastability of Ce2Zr2O8 compared to its stable decomposed products has been determined.