An opto-electric hybrid board includes: an electric circuit board including an insulative layer having front and back surfaces, and electrical interconnect lines formed on the front surface of the insulative layer; an optical element mounted on a surface of the electric circuit board with the electrical interconnect lines formed thereon; and an optical waveguide including a core and formed on the back surface of the insulative layer of the electric circuit board. The core includes at its end portion a reflecting surface capable of reflecting alight beam to propagate the light beam between the core and the optical element. The insulative layer is made of a light-transmissive material. A portion of the insulative layer corresponding to an optical path between the reflecting surface of the core and the optical element is in the form of a lens portion.