The thermal decomposition of ammonium perchlorate has been extensively Studied ill the past. Nevertheless, the various results published illustrate, oil the one hand, significant differences regarding the influence of different parameters oil the decomposition and on the other hand. a lack Of useful quantitative laws to predict the thermal behaviour of this crystal Under a range of conditions (temperature. duration of exposure. presence of confinement). With the aid of a set of specific experimental devices (TG/MS, SEM, FTIR), the purpose of this paper is twice to clarify the differences observed in the literature ill order to understand the detailed decomposition kinetic process of ammonium perchlorate and to establish analytical laws to facilitate the prediction of the thermal behaviour of ammonium perchlorate.