Abstract: A security device for a door comprises a U-shaped reinforcing plate on the vertical edge of a door on the deadbolt side of the door and an elongated frame plate. The door reinforcing plate and the frame plate are made of a hardened material such as cold rolled steel. The door reinforcing plate extends substantially the entire length of the door. A force applied to the door by a would-be intruder is transmitted from the deadbolt to the door reinforcing plate and the elongated frame plate, which then distribute the force over the vertical edge of the door and a significant part of the frame, respectively.