A printed circuit board including an optical waveguide and a method of manufacturing the board. In the board, the optical waveguide includes a metal layer extending portion integrally connected to a metal layer constituting a mirror formed in the optical waveguide. Since the method creates the mirror using electroless plating, which is typically used in a process of manufacturing general printed circuit boards, it is suitable for the manufacture of printed circuit boards having a large area, and the mirror has high reflectivity and is efficient in terms of material consumption.