To develop an efficient recovery process of zinc from molten fly ashes, the release of zinc from the ashes was investigated during heat treatment with and without the addition of polyvinyl chloride or carbon. Change in the form of zinc in the ashes with temperature was clarified by sequential leaching analysis. Two kinds of molten fly ash obtained from different melting processes were used which contained ZnO or ZnCO(3) as the major zinc component, respectively. In the case of PVC addition, formation of zinc chloride was identified in the ZnO-based sample front 573 K, and volatilization or zinc was observed from 873 K. In the ZnCO(3)-based sample, the volatilization of zinc was accelerated from the melting point of CaCl(2), while zinc chloride was not observed in the solid phase. When carbon added to the ashes, remarkable volatilization of zinc was observed from the boiling point of ZnCl(2), and the extent of zinc release depended on the chlorine content of the ashes.