Zirconium nitride (ZrN) nanopowders were prepared by carbothermic nitriding of precursor in flowing nitrogen. The precursor was mixture of zirconia gel and carbon black which was obtained by using internal gelation process. The heat treatment behavior of the precursor material, phase composition, morphology and microstructure of powder products were characterized by simultaneous thermogravimetric analysis and differential scanning calorimetric analysis (TGA/DSC), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). With increase in temperature, nitriding level increased. Pure ZrN phase was achieved at 1400°C and the particle size of the powder product was in nanometers. Carbon plays an important role of reductant in nitridation process and the carbon to zirconium mole ratio should be properly controlled to ~2 such that desired ZrN products could be prepared.