Abstract: An automatic portion-cutting machine measures the shape of a fish fillet, calculates its corresponding volume and weight, and cuts the fillet to create portions of a predetermined size. In the preferred embodiment disclosed herein, fish fillets are advanced along a conveyor to allow these operations to take place. An optical monitoring station along the conveyor sends data relating to the shape of the fillet to a processing unit which calculates the weight of the fillet and actuates a cutting unit to cut the fillet at locations corresponding to the portion size desired.