We have investigated the source of O(1D) atoms in the auroral ionosphere using sounding rocket data. Previously, it has been shown that the conventional sources of O(1D) atoms in the aurora, dissociative recombination of O2+ and electron impact excitation of atomic oxygen, fail to explain the measured 6300¿ volume emission rate profile. We suggest that the atom-atom interchange reaction of N(2D) with O2 can be the major source of auroral 6300¿ emission if O(1D) is created with high efficiency.