The invention relates to a fibre guide channel for the pneumatic transport of individual fibres, which are combed out of a fibre band by an opening cylinder that rotates in an opening cylinder housing of an open end spinning frame, to a spinning rotor running at high speed in a rotor housing that can be subjected to a negative pressure. On the inlet side, the width of the fibre guide channel that is located in a cover element for closing the rotor housing is adapted to the mountings of the opening cylinder. According to the invention, both the inlet opening (25) and the outlet opening (26) of the fibre guide channel (11) are configured as slots, the maximum extension (B) of the inlet opening (25) running parallel to the rotational axis (27) of the opening cylinder (9) and the maximum extension (L) of the outlet opening (26) of the fibre guide channel (11) being rotated about a longitudinal axis (28) of the fibre guide channel (11) by 90° ± 10° in relation to the maximum extension (B) of the inlet opening (25).