Abstract: A compost handling machine comprising a carriage to support the machine for movement along a composting bay, and a compost agitating and conveying assembly to agitate compost in, and to move the compost along the bay. The agitating and conveying assembly includes a conveyor subassembly and a drum subassembly. The conveyor subassembly includes a plurality of lifting cleats that, in use, are moved around a closed path to lift compost in the bay and move the compost rearwardly therein. The drum subassembly includes an agitating drum extending between and supported by a pair of support arms, and the drum is rotated to agitate and comminute the compost in the bay.