An open-end spinning machine having an open-end spinning unit with novel apparatus for withdrawing impurities released in the spinning unit. An impurity releasing duct outlet of the sliver separation housing of the open-end spinning unit extends from said housing and has substantially the same cross-sectional inner height dimensions as those of the cleaning aperture, while a connecting tube inlet joined to said outlet is substantially conically flared, a gap being provided between said outlet and said inlet for the sucking-in of additional air.
