W-Cu nanocomposite powders were successfully synthesized by the ball-milling and hydrogen-reduction process using W and CuO powders. After the ball-milling of 20 h, the crystalline size of W was measured as about 40 nm. The ball-milled W-CuO mixtures were hydrogen-reduced at temperature of 300 o C to fabricate the W-Cu nanocomposite powder. The reduced powder was composed of nanosized W and Cu particles. Fully densified W-Cu compacts can be fabricated by the sintering at 1200 o C for 1 h with the heating rate of 10 o C/min in H 2 atmosphere. The sintered W-Cu composites showed homogeneous microstructure with fine grains.