Abstract: A screw pump having a unit which includes a drive screw and at least one impeller screw that meshes therewith, arranged within a casing that sealingly encloses the screws, each impeller screw on the pressure side being provided with a pin mounted in a sleeve, the interior of which communicates with the suction side through channels in a pump housing and the drive screw. There is a disc-like packing between an end surface of each sleeve and an end wall that closes the pressure side of the housing, through which end wall the channels partially extend, and through which a drive shaft is extended for the drive screw. The invention provides that each sleeve has one or more deformation zones on a side thereof remote from the packing, and facing a fixed surface in the housing, which zones are arranged to abut the fixed surface in the housing.