An impeller (1) for a molten metal pump having a cylindrical body comprised of a refractory material. The cylindrical body includes generally coplanar top (2) and bottom (12) surfaces. A central bore (4) is provided in the top surface (2) to provide a point for mating with a shaft. A plurality of circumferentially spaced passages (6) extend from the top surface (2) to a side wall (8) of the impeller (1), each of the passages being separate and preferably having an inlet opening (5) which is equal to or less than the corresponding outlet opening (9) in size.
