Provided herein is a method for the synthesis of nanocrystalline diamond (NCD) wires by depositing nanocrystalline diamond on Si nanowires using chemical vapor deposition methods. Seeding the nanowires in solutions containing nanodiamond powers, NCD wires are fabricated in typical CVD growth conditions within a very short time. NCD wires were 0.5-5 μm in diameter, depending on the growth time, with lengths in the range of 20-100 μm. The average elastic modulus determined by nanoindentation is 474.16±13.48 GPa. The unique mechanical properties of the NCD wire make it a potential material for active components of both electronic and electromechanical devices.