The correlation between the ash composition of various incinerated waste residues and their melting temperatures was examined by using their chemical composition parameters. There was a low correlation between the melting temperatures and the acidic oxide content in the ashes. However, the composition parameters derived from the basic oxides showed a good correlation with the ash melting temperature. The composition parameter, P7, which is defined as the ratio of basic oxides (CaO+MgO+K2O+Na2O) to acidic oxides (SiO2+Al2O3+Fe2O3), showed a strong correlation with the ash melting temperature. By fitting the composition parameter to the experimental data, the correlation equation for the half fluid temperature (HFT) was found to be HFT=426.77P7^(2)-736.76P(7)+1592.3 with a correlation coefficient of 0.91. The correlation equation could be used to predict the melting temperatures of various waste incineration residues. The relative error between the measured and predicted melting temperature was approximately 5%. Overall, these parameters and correlation equations can be used to predict and reduce the melting temperature of incineration residues.