A washing machine (100) has a drawer (1) having at least one compartment (10a, 10b, 10c, 10d) for receiving an agent for treating laundry, a supporting structure (2) on which the drawer can slide and a removable retaining device (4) connectable to the supporting structure for delimiting a movement of the drawer with respect to the supporting structure. The removable retaining device is connected to the supporting structure by moving the removable retaining device along a fixing direction. The supporting structure has an engagement element (220) and the removable retaining device has a releasable locking element (420) engaging with the engagement element such that, when the removable retaining device is moved along the fixing direction in order to be connected to the supporting structure, the releasable locking element locks the retaining device in a connected condition.