Silicon nitride nanorods were fabricated from Si, NaN3, and sulfur powder at 250 degrees C. XRD patterns show that the final product is mixed alpha- and beta-Si3N4. SEM, TEM, and HRTEM images reveal that the product was composed of crystalline Si3N4 nanorods with diameters in the range of 70-400 nm and lengths up to 3 pm. It is found that sulfur plays a crucial role in the low-temperature formation of Si3N4 powders. Low reaction temperature and cheap raw materials make it possible for large scale synthesis of Si3N4 nanomatetials.