A cable end-piece for a cable which slides in a flexible sheath. The end-piece includes a hollow tubular body which is closed by a base. The base has an opening for the passage of a cable therethrough. The base includes an extension which has an outer surface and an inner surface. The inner surface is provided with a seal to sealingly contact the cable. The outer surface has at least one groove which is connected to the inner surface by means of channels. The material from which the seal is made also fills the channels.