This research was designed to develop a separation method for partially overlapped peaks on derivative therm ogravimetry (DTG) curves and to apply this technique to estimate the dehydrochlorination kinetics of PVC (Polyvinyl Chloride). It was assumed that two peaks might be responsible for the independent dehydrochlorination reactions of two PVC compounds. Dehydrochlorination kinetics of PVC were inves- tigated using a thermogravimetric analysis (TGA) system at heating rates of 0.75, 1, and 1.25 Wmin under a nitrogen atmosphere. A key hypothesis for applying the separation method was that, under dynamic operations, there would be a unique temperature region in which each compound would decompose uniquely. Firstly, the apparent kinetic parameters and initial mass of the thermally-more-stable PVC compound were estimated from the partial DTG curve in the range where only this compound might decompose. Then, the dehydrochlorination kinetics of the thermally-less-stable PVC compound were elucidated by analyzing its TGA curve that was derived by subtracting the TGA curve of the more-stable PVC compound from the original curve. It is essential to separate the overlapped peaks on the DTG curves to accurately interpret the kinetics of the independent reactions. This separation technique can be applied to analyze the kinetic parameters of two independent reactions provided that there are unique temperature regions in which each compound decomposes solely.