An assembly for a drug delivery device, comprising: a piston rod, which is in engagement with a guiding element such that, when the piston rod is rotated, the piston rod is caused to axially move as a result of its cooperation with the guiding element, a housing, a compression spring, wherein the compression spring is compressed during the setting of a dose of a drug, a sleeve member, a rotation member, wherein the sleeve member is rotationally fixed and axially moveable with respect to the rotation member, wherein a rotation of the rotation member during the dispensing of a dose causes a rotation of the piston rod, a dose setting member which is configured to be rotated in a dose setting direction in order to set the dose, wherein a rotation of the dose setting member in the dose setting direction causes a rotation of the rotation member in the dose setting direction, and wherein the rotation member is coupled to the dose setting member by means of a drive shaft, an actuator which is configured to be operated in order to dispense the dose of the drug, wherein the compression spring is enabled to relax when the actuator is operated, and a locking member which is configured to inhibit a rotation of the rotation member in a dose dispensing direction during the setting of the dose, thereby inhibiting the relaxation of the compression spring, wherein the locking member is fixed with respect to the housing during the setting of the dose and, when the actuator is actuated, is disengaged from the housing allowing a rotation of the rotation member in the dose dispensing direction, wherein the compression spring abuts the sleeve member and wherein the compression spring and the sleeve member are configured such that a relaxation of the compression spring effects a rotational and an axial movement of the sleeve member in a proximal direction away from a dispensing end of the device, thereby causing a dispensing of the dose from the drug delivery device, and wherein the compression spring is arranged between a bearing surface of the housing and the sleeve member, and wherein the compression spring exerts a force on the sleeve member which is directed in proximal direction. a piston rod, which is in engagement with a guiding element such that, when the piston rod is rotated, the piston rod is caused to axially move as a result of its cooperation with the guiding element, a housing, a compression spring, wherein the compression spring is compressed during the setting of a dose of a drug, a sleeve member, a rotation member, wherein the sleeve member is rotationally fixed and axially moveable with respect to the rotation member, wherein a rotation of the rotation member during the dispensing of a dose causes a rotation of the piston rod, a dose setting member which is configured to be rotated in a dose setting direction in order to set the dose, wherein a rotation of the dose setting member in the dose setting direction causes a rotation of the rotation member in the dose setting direction, and wherein the rotation member is coupled to the dose setting member by means of a drive shaft, an actuator which is configured to be operated in order to dispense the dose of the drug, wherein the compression spring is enabled to relax when the actuator is operated, and a locking member which is configured to inhibit a rotation of the rotation member in a dose dispensing direction during the setting of the dose, thereby inhibiting the relaxation of the compression spring, wherein the locking member is fixed with respect to the housing during the setting of the dose and, when the actuator is actuated, is disengaged from the housing allowing a rotation of the rotation member in the dose dispensing direction, wherein the compression spring abuts the sleeve member and wherein the compression spring and the sleeve member are configured such that a relaxation of the compression spring effects a rotational and an axial movement of the sleeve member in a proximal direction away from a dispensing end of the device, thereby causing a dispensing of the dose from the drug delivery device, and wherein the compression spring is arranged between a bearing surface of the housing and the sleeve member, and wherein the compression spring exerts a force on the sleeve member which is directed in proximal direction.