A tamper evident assembly for retaining a plunger and piston within a barrel of a syringe including an elongated tether and a cover connected to the tether and concurrently disposed in an operative position on the syringe. A connector assembly adjustably and fixedly interconnects the tether to the cover in the operative position, wherein the cover is connected in covering relation to a discharge port of the syringe concurrently to a proximal end of the tether being connected to the syringe barrel in a removal preventative relation to the piston. Movable adjustment of the tether relative to the connector assembly defines a retaining segment disposed into a taut, fixed length orientation between the proximal end of the tether and the cover, to further define the operative position.