The invention relates to a centrifugal pump, especially for blood, comprising a pump rotor which is arranged in a rotational manner and without a bearing in a liquid-tight and gas-tight closed housing, except for at least one inlet opening and at least one outlet opening. The rotor is also the rotor of a drive motor. The rotor is symmetrical with respect to the centre plane thereof and comprises an upper and a lower covering. The rotor and/or the pump housing are formed in such a way that the axial distances between the upper and the lower coverings and the upper and lower housing walls are smaller in the radially inner region of the rotor than in the radially outer region. In the radially inner region of the rotor, each lateral rotor chamber comprises a flow-restrictor gap which, when in operation, influences back flows oriented in a radially inward manner in the lateral rotor chambers, such that during an axial deflection of the rotor above and below the rotor, various pressure distributions appear, enabling forces acting upon the predominant surface of the coverings to be produced, the forces bringing about an axial stabilisation of the rotor and acting, in the same manner, against tilting of the rotor inside the housing.