A simple method was derived for determining the autoignition temperature of solid energetic materials with high activation energies. The calculation is straightforward. The only parameters employed are the activation energy of the decomposition reaction and the temperature at the beginning of the steepest slope on a single non-isothermal DSC or DTA exotherm. The energetic materials investigated were the conventional explosives RDX, HMX, Tetryl, PETN, TNT and nitrocellulose. Published DSC data for NTO explosive and its salt derivates were cited to predict their autoignition temperatures. One energetic polymeric binder, GAP, and its mixtures with RDX or HMX were also examined. The autoignition temperatures obtained for the tested materials are in very good agreement with literature data.