Abstract: Fish filleting apparatus has a base on which is supported a pair of substantially parallel mandrels spaced by a slot the confronting surfaces of which form cutting edges flanked by longitudinally extending grooves. Above the level of the mandrels is a pair of spaced apart guides which support a dressed fish with its back accommodated in the slot and its sides extending upwardly. An extruder blade is pivoted at one end on the base for movement through the slot in a direction toward the base. Such movement of the blade causes the spine of the fish and bones attached thereto to be extruded through the back of the fish and the two sides of the fish to be separated from one another.