Changes in the nitrogen content of Ti(C,N)-based cermets during powder mixing and sintering processes were investigated and the denitrification mechanism was re-evaluated. The denitrification of N-containing cermets occurrs mainly during the powder mixing process, and is relatively small during sintering periods. Denitrification during powder mixing is caused by oxidation of the Ti(C,N) powders in contrast to denitrification during sintering, which is caused by the decomposition of the nitrides due to the high nitrogen partial pressure. It was concluded that the main source of oxygen for the powder oxidation was the water present in the ethanol solvent.