Abstract: A fuel injection pump for internal combustion engines, having a pump piston that is guided axially and rotationally movably in a cylinder bore of a cylinder liner and that with a face end defines a pump work chamber. The fuel injection pump pumps a quantity of fuel that is divided into a preinjection quantity and a main injection quantity. On a jacket face, this pump piston has known oblique grooves for the high-pressure pumping diversion process, and also a recess, which cooperates with an annular groove in the cylinder bore and with a control opening which discharges into a low-pressure chamber, and on its end face the piston has a cutout formed by two different, deep shoulders; the cutout is recessed within the annular groove continuously and cooperates with a first control opening that discharges into the low-pressure chamber.