A new calorimeter especially built for the measurement of the heat release rate and effective heat of combustion of composite materials is presented. Two procedures can be used to obtain these data: the first one is based on the direct measurement of the convective and radiant heat liberated by the flame, the second involves oxygen consumption measurement. Preliminary experiments were carried out with a gas burner to calibrate and check the inertia of the thermal method. In a second step, measurements were performed on Downloaded from 483 PMMA and PVC samples. The results obtained with both methods are very similar and in agreement with literature values.