Abstract: A yarn-stuffing system is disclosed in which the yarn is drawn in and expanded by a pneumatic nozzle and the yarn and air are conducted longitudinally to a discharge zone remote from the nozzle. The air is vented laterally in the discharge zone while the yarn is inhibited in its discharge to be stuffed and is periodically released to emerge stepwise from the discharge zone. The preferred apparatus includes a constricted yarn-stuffing and discharge zone which is expandable to allow slip of the stuffed yarn until pressure is relieved behind the stuffed yarn and returns to its constricted position until the pressure again rises as a result of obstruction of the vent ports.