Abstract: Sorting unit (1) for belt conveyor plants, of the type comprising a first sorting conveyor belt (7) extending between first transmission rollers (11) and revolvingly oscillating around a first oscillation axis (X-Y), extending in parallel and close to one of its longitudinal edges. A second sorting belt (8) is also provided, which extends between second transmission rollers (12) and is placed aside the first sorting belt at the opposite side to the first oscillation axis, as well as revolvingly oscillating around a second oscillation axis (X'-X') running in parallel and in correspondence of its longitudinal edge placed at the opposite side with respect to the first sorting belt.