The present invention describes a root and leaf topping system of onion bulbs which can remove leaves and roots from onions of all sizes. The apparatus comprises of onion storage belt, observation belt, leaf cutting unit, root cutting unit and grading unit arranged together along with an engine for operation. The leaf cutting unit comprises of counter rotating round bar and cutting blade, wherein counter rotating action pushes down the onion leaf in downward direction and cuts the leaves at appropriate distance from the bulb making them round shaped and they proceed towards root cutting unit comprising of counter rotating round and square bar which pushes down the root and cuts it at appropriate distance. The processed onions move towards the grading unit where they are separated based on size and the waste that is generated in the process is carried to the bin by the waste carrying belt.