Aluminum nitride (AlN) was synthesized at 1000-1400 degrees C from a mixture of alumina and carbon powders using 2.45 GHz microwaves in a N-2 atmosphere. High nitridation ratios (>0.90) were obtained in the temperature range 1200-1400 degrees C. The apparent activation energy of the carbothermal reduction and nitridation (CRN) reaction using 2.45 GHz microwave irradiation was calculated from the nitridation ratio. The value obtained, 79.9 kJ/mol, is 11% of the energy reported for conventional synthesis using -Al2O3 as the raw material. This result indicates that 2.45 GHz microwave irradiation could promote the kinetics of the CRN reaction, and AlN could be effectively synthesized at low temperature.