Foot prosthesis, comprising an upper part, and a lower part that is placed on the ground when walking, wherein the upper part and the lower part are connected to each other via an elastic damping element arranged in the heel area, and the upper part and the lower part, forming a spring, extend one above the other and spaced apart from each other into the area of the forefoot, wherein at least one filling piece (15) is inserted between the upper part (3) and the lower part (4) in the area between the damping element (9) and the forefoot (5), which filling piece (15) increases the flexural stiffness of the upper and lower part coupled via the filling piece during walking.