Abstract: A safety assembly for an injection syringe, which syringe consists of a liquid container arranged or to be arranged within a casing (10) and having a piston (17) shiftable therein, a piston rod unit (1) provided with an external actuating element (3) and coupled or to be coupled with the piston, a needle foot (20) latched or to be latched at the other end of the casing with a hollow needle (27) communicating or to be communicated with the interior of the liquid container, said piston rod unit being provided with means (13) for unlatching the needle foot and to couple it with the piston rod unit, in order to allow to retract said foot together with the needle into the casing. According to the invention the piston rod unit comprises two parts (3, 5) which are mutually movable in the axial direction, one part being formed by the piston rod (1) or being connected thereto, and the other one comprising an unlatching element (8, 13, 22).