Abstract: In a filleting machine for fish for the production of fillets entirely free of bones and including the belly flaps the tail portions of the fillets are cut free by means of belly filleting knives, back filleting knives and separating knives, the fillets fall down with their tail ends, the back portions of the fillets are cut free by means of back filleting knives and upper pinbone knives and are engaged to drop down, adhering to the belly portions of the fish only at the end of the belly, these adhering portions of the fillets are pressed down by hold down means meanwhile lower pinbone knives are cutting into the fish through the skin portion situated between the upper and the lower pinbone cuts and are cutting free the belly flaps, which will be separated from the skeleton of the fish by means of rib knives, and the strips containing the pinbones are separated from the skeleton by means of strip cutting knives.