TiN particulate/Ti5Si3 matrix composite powder has been synthesized from Ti and Si3N4 powders employing high-energy ball milling. The milled powders have been characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. TiN/Ti5Si3 composite powder is formed by a displacement reaction between Ti and Si3N4 during milling, and the reaction progresses in a mechanically induced self-propagating reaction form. The milled powder consists of TiN crystallites of a few hundred nanometers embedded in Ti5Si3 matrixes. After 20 h of milling, the crystallite size of TiN becomes about 5 nm.