We studied composite anion exchange membranes made from poly(2,6-dimethyl-1,4phenylene oxide) (PPO) with grafted 1,4-diazabicyclo[2.2.2]octane (DABCO) and Mg/Al lamellar double hydroxide particles as inorganic filler. The mechanical and conductivity properties were measured in fully humidified conditions. The activation energy for conductivity amounts to (0.20 ± 0.01) eV. The degradation of the anion exchange membrane in 2 M NaOH at 60 °C was investigated during 168 h following the ionic conductivity, water uptake and ion exchange capacity as function of the alkaline treatment time. The degradation is rapid within the first hours and then slows down. The degradation was also studied by thermogravimetric analysis and FTIR spectroscopy, showing the various decomposition phenomena of the composite.