Abstract: A system for simultaneously mounting a plurality of accessories such as panniers, baskets, trailer hitch and trailer, luggage carrier, wheel fender, etc. to a bicycle frame includes an upper mounting block rigidly attachable to the frame below the bicycle seat, and two lower stirrup members rigidly attachable to the frame adjacent the wheel axle on either side of the wheel. The upper mounting block has a socket for holding a tow bar and slots for mounting a luggage carrier, both of which have legs which are lockably inserted into receiving slots in the stirrup members. A key lock locks the mounting block to the bicycle frame and the accessories to the mounting block. Accessories may be locked to the carrier.