Abstract: An alarm switch for indicating when a latch or dead bolt for a door or window is locked or unlocked comprises a switch casing adapted for mounting on the exterior portion of the door or window frame or door or window; an electrical contact assembly mounted in the casing; a contact assembly actuating member mounted in the casing in position to change the electrical state of the contact assembly by movement of the actuating member from a deactuated to an actuated position, the actuating member being resiliently biased toward its deactuated position but being in position to engage the dead bolt or latch and move to its actuated position when the door or window is shut and the dead bolt or latch is locked, the actuating member being accessible to the door or window latch or dead bolt through an opening in the casing; and electrical terminals on the contact assembly adapted to be connected to leads leading to a remote alarm system that indicates to the alarm circuit when the door or window bolt or latch is opened.