The present invention relates to a dose setting mechanism for a drug delivery device and a method of using same. The mechanism comprises a housing, a mechanism member (7) movable in a first axial direction relative to the housing during dose setting and movable in a second, opposite axial direction relative to the housing during injection, wherein the mechanism member (7) is designed and arranged such that the mechanism member (7) is able to change its condition between a first condition preventing movement in the second axial direction and a second condition allowing movement in the second axial direction, and a switching member (9) forcing the mechanism member (7) to change from its second condition into its first condition at a predefined position of the movement in the first axial direction during dose setting.
