Abstract: A rear fender, or mudguard, is provided to defect tangential spray from the rear wheel of a bicycle. It emanates from the underside of the seat, being cantilevered over the rear wheel. The fender is attached by way of its design to the underside of the seat, being held in place by a forward tongue section and a middle section containing notches which attach to the metal seat rail supports. No metal fasteners are needed to attach and detach the fender. The fender is comprised of any available thermoplastic or thermosetting materials which can be formed, shaped, or fabricated by conventional means. These materials may contain additives such as colorants, reinforcing aides, stabilizers, and other compounding aides and fillers.