Thermal degradation at 180° in air of PVC stabilized with an equimolar mixture of Ba and Cd stearates has been studied. The “unreacted” stearates were separated by filtering tetrahydrofuran solutions of samples. The filtration and thermal degradation were examined by means of infrared spectroscopy in the range 1400–1800 cm −1. It has been demonstrated that, during the thermal stress, CdCl 2 is accumulated in the sample and that the presence of Ba stearate supports only the consumption of Cd stearate.