A method assembles a plug on a multi-core sheathed cable which extends in a longitudinal direction and has multiple wires surrounded by a cable sheath. A sealing element made of a sealing material is applied to the multiple wires. The sealing element has individual passages formed through the sealing material for the wires. Subsequently, the wires are assembled in a plug housing, wherein the plug housing has an opening at a rear end thereof, and the sealing element is inserted into the opening and shifted preferably along the wires such that the sealing element sits in the opening in a sealing manner. A sealing coating is then applied, which extends from the rear end of the plug housing to the cable sheath.