A joining system for use in furniture and furnishing items with a bottom and a shoulder has a front actuation axis under the bottom and includes a front joining unit and a rear joining unit positioned between the bottom and the shoulder of the furniture or furnishing item. A connection group is inserted in each front and rear joining unit and is aligned with a symmetry axis of the bottom, and a blocking group of the front and rear joining units is attached beneath the thickness of the bottom. The front joining unit provides an actuation and supporting member toward the rear joining unit, and the blocking group provides a grub screw inserted in a casing and caused to slide by way of a conical rack and pinion system, to be received in a bevel in the pin.