An extendable vehicle load floor mounting assembly for attachment to a vehicle cargo space floor having a plurality of factory bolt openings includes a base frame, a plurality of bolt flanges carried by the base frame and a plurality of flange bolt openings in the bolt flanges, respectively. The flange bolt openings in the bolt flanges are configured to correspond in position to the factory bolt openings, respectively, in the vehicle cargo space floor. A plurality of bolts are adapted for extension through the flange bolt openings and the factory bolt openings, respectively. An extendable vehicle load floor is slidably carried by the base frame.