Abstract: A conventional underwater plastic pelletizer of the type using a rotatable knife hub is improved by securing to the knife hub a diverter plate for confining the flow of inlet water to the region adjacent the face of the die plate. The cutting knives are mounted on the rotating hub at a rake angle with respect to the hub center and tilted at an angle with respect to the surface of the die plate so as to effectively pull a cut pellet away from an extruded plastic strand, and the die plate is heated by an organic heat exchange fluid. The result is a substantial reduction in orifices frozen off by cooled polymer.