A vacuum pump rotor suitable for use in a vacuum pump is described for a vacuum pump that comprises a regenerative pumping mechanism. The rotor has a generally disc-shaped configuration and is mounted on an axial shaft for rotation relative to a stator of a vacuum pump. The rotor has a first and second opposing surface on which a rotor formations are disposed, each rotor formation defining a portion of a pump stage formed between the pump rotor and a stator for pumping gas from an inlet to an outlet in the same radial direction along the first and second opposing surface. A conduit is provided to interconnect the portions of the pump stage and assist with pressure imbalance that might occur on opposing sides of the rotor.