The heat of combustion of aluminum carbide (A14C3) in oxygen was measured by means of bomb calorimetry. The solid product of the combustion consisted of alpha aluminum oxide and another crystalline form of alumina, which was characterized as delta alumina. The heats of combustion were corrected for the formation of the delta aluminum oxide. The results, when combined with the heats of formation of alpha aluminum oxide and carbon dioxide, yielded -49.7 kcal mole-1 for the standard heat of formation of aluminum carbide at 298.15°K with an estimated overall uncertainty of ±1.2 kcal mole-1.