Abstract: An innerduct is disclosed which can fit inside a preexisting conduit and extend along the length thereof or can be directly buried with a plow or in an open trench, for receiving transmission cables and, in particular, fiber optic cables. The innerduct is formed by coextruding first and second materials, the material for the inner portion of the innerduct including a lubricous material impregnated therein so that friction is reduced between the inner surface of the interduct and cables which are pulled therethrough. Ribs can be provided on the inner and outer surfaces of the innerduct of the duct can be formed with undulated walls so as to further reduce friction between same and cables slid therethrough by minimizing the surface contact between these elments. The ribs and/or undulations also faciliate the dissipation of heat due to friction of assembly, heat during the extrusion process, and from ambient sources of heat.