The thermal decomposition kinetics of a mixture of high-energy oxidizers ammonium dinitramide (ADN) and guanylurea dinitramide (GUDN) have been studied by nonisothermal differential scanning calorimetry (DSC). Friedman's and Vyazovkin's advanced isoconversional (AIC-V) methods were used to investigate the dependence of activation energy (E-a) on conversion (alpha). A strong dependence of E-a on alpha was observed, indicating a complex decomposition process. E-a is similar to 165-175 kJ mol(-1) at the start of the reaction, then reaches a maximum of similar to 196-199 kJ mol(-1) at alpha = similar to 0.4, followed by a strong decrease to similar to 135 kJ mol(-1) near the end. E-a has also been determined for the mixture and the individual components using Kissinger's method. Our results suggest that the decomposition of ADN greatly influences the observed E-a dependence on alpha. This is further supported by Fourier transform infrared (FTIR) results and the enthalpy values of exothermic decomposition. (C) 2008 Elsevier B.V. All rights reserved.