Aluminum nitride and silicon nitride nano-powders were synthesized through a chemical reduction, of AlCl3 and SiCl4 by sodium in liquid ammonia. The product powders were amorphous and spherical agglutinating particles ranging from 1 to 10 nanometers in diameter. Single-crystalline aluminum nitride (AlN) and silicon nitride (Si3N4) nanowires with hexagonal structure were prepared by heating the amorphous nano-powders at 1300°C through 1450°C. The products obtained were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The results revealed that the products were single-crystalline AlN and Si3N4 nanowires. The diameters of the nanowires ranged from 30 to 200 nm, and the lengths were from several micrometers to several decades of micrometers.