Abstract: A pellet-forming apparatus is provided for extruding high moisture materials in a low-pressure extrusion apparatus having an extruding cylinder and a cooperative extruding rotor. The rotor extends axially through the elongated cylinder and is formed with multi-tier extruding surfaces that are configured and positioned to be radially spaced with respect to the interior surface of the cylinder and form a pressure zone to effect radial displacement of the material through passages formed in the cylinder wall and be extruded exteriorly of the cylinder. The rotor preferably consists of a series of configured plates arranged along a common axis to form a combined auger-shaped extruding rotor. A feed conveyor comprising a helical flight auger is provided in preceding axial relationship to the extruding cylinder for feeding of material into the cylinder without substantial pressure buildup.