Nanocrystalline NbN powder was synthesized by the direct nitridation of amorphous Nb2O5 powder with high BET surface area. X-ray diffractometry analysis indicated that the cubic-phase NbN powder could be obtained by nitridation at 650degrees-800degreesC for 3-8 h. Transmission electron microscopy images showed that the particle sizes were in the range of 15-40 nm. The effect of the nitridation temperature and holding time on the powder properties was discussed.