A new technique for simultaneous acoustic emission (AE) and differential thermal analysis (DTA) measurement is described. The technique has been successfully utilized to monitor some mechanical events occurring during dehydration, decomposition, and phase transition of NaN₃, alkali perchlorate (MeClO₄ where Me=Na, K, Cs), CsCl, NH₄Cl, NH₄Br, and KNO₃ for which the new results are reported. It is noticed that the events which cannot be detected by DTA are monitored by AE.