Abstract: An open-end spinning unit is provided which has a spinning rotor open on one side and has a closed bottom and lateral sides. A closing component covers the open side of the rotor and includes a fiber supply duct directed at a slide wall part of the lateral wall of the rotor, a yarn take-off duct, and a suction duct. To optimize the air conveyance of fiber to the slide walls, at least a part of the suction duct orifice is disposed in the radial direction of the rotor closer to the slide wall than to the orifice of the fiber supply duct.