A color coding is applied to medical guide wires by coloring portions of the guide wire to distinguish similar guide wires and guide wire portions from a particular manufacturer. The metallic elongate core can be colored using various methods such as electrochemical processes, sputtering, electroplating, and laser inducing microstructures to alter the surface characteristics of the elongate metallic core. Alternatively, the outer layer of the guide wire can be color coded by using non-standard colors or by introducing a colored band on the guide wire.