Laboratory tests were carried out on the wear resistance, corrosion resistance and mechanical properties of titanium nitrided in nitrogen stream at 850°C for 16∼80 hr. The wear resistance of titanium was remarkably improved by nitriding. According to the results of sliding experiments, nitrided titanium showed satisfactory surface properties in combinations with the following materials: Cast iron, hard chromium plating and nitrided titanium itself respectively in unlubricated conditions; bronze, cast iron, carbon steel, low alloy steel, Carbaite, bakelite, hard chromium plating and nitrided titanium itself respectively in lubricated conditions. On the whole, the corrosion resistance of titanium was not affected adversely by nitriding and, further, it was interesting to note that the nitriding even improved the resistance in reducing environments. The effect of nitriding on the mechanical properties of titanium was negligible.