Abstract: A locked bill stacker in which a slide is mounted on the cash box for movement between a first position at which it blocks the mouth of the cash box and a second position at which the mouth is open. When the stacker is in operative relationship with a bill acceptor, movement of the slide from the first to the second position locks the stacker to the acceptor. When the slide is moved from the second position to the first position the slide is locked in the first position. A latch is provided to prevent the slide from accidentally moving from the first position to the second position before the stacker is positioned in operative relationship with the acceptor.