A blood pump (1) comprises a pump casing (2) having a blood flow inlet (5) and a blood flow outlet (6) connected by a passage (7), and an impeller (3) arranged in said pump casing (2) so as to be rotatable about an axis of rotation (9). The impeller (3) is provided with blades (4) sized and shaped for conveying blood along the passage (7) from the blood flow inlet (5) to the blood flow outlet (6), and is rotatably supported in the pump casing (2) by a first bearing (10) at a first axial end of the impeller (3) and a second bearing (20) axially spaced apart from the first bearing (10). The first bearing (10) comprises a projection (11) extending along the axis of rotation (9) and connected to one of the impeller (3) and the pump casing (2) and a cavity (13) in the other one of the impeller (3) and the pump casing (2), the projection (11) comprising an enlarged portion (12) that engages the cavity (13) such that the first bearing (10) and the second bearing (20) are arranged to bear axial forces in the same axial direction.