A counter rotating helico-axial pump is provided, the pump comprising: (a) an inner rotor comprising a plurality of outwardly extending helico-axial impeller vanes; (b) a hollow outer rotor comprising a plurality of inwardly extending helico-axial impeller vanes; (c) a single driving device configured to drive the inner rotor or the hollow outer rotor; and (d) a force transmission coupling joining the inner rotor and the hollow outer rotor and configured to permit rotation of the inner rotor and hollow outer rotor in opposite directions; wherein at least a portion of the inner rotor is disposed within the hollow outer rotor, and wherein the inner rotor, the hollow outer rotor and the helico-axial impeller vanes define a fluid flow path, and wherein the inner rotor and hollow outer rotor are configured such that at least some of adjacent helico-axial impeller vanes are configured to rotate in opposite directions.