A method and device of cleaning the rotor (6) of a rotor spinning machine are provided in which, after the opening of a spinning unit, there are sucked off from the rotor (6) fibres and impurities being released from the inner surface of the rotor by pressure air applied to said inner surface. The cleaning pressure air is led into the rotor (6) in at least two air streams producing in the rotor (6) a symmetrical streaming in one and the same direction and the supplied air, together with the released impurities, is sucked off through the centre of the inlet aperture (63) of the rotor (6).