A slurry pump impeller which includes a front shroud and a back shroud each having an inner main face with an outer peripheral edge and a central axis, a plurality of pumping vanes extending between the inner main faces of the shrouds, the pumping vanes being disposed in spaced apart relation. Each pumping vane includes a leading edge in the region of the central axis and a trailing edge in the region of the outer peripheral edges of the shrouds with a passageway between adjacent pumping vanes. Each passageway has associated therewith a discharge guide vane, each discharge guide vane being disposed within a respective passageway and located closer to one or the other of the pumping vanes and projecting from the inner main face of at least one of the or each shrouds.