Abstract: First and second plates are hinged together and designed such that the first plate can be secured to the inside frame or jamb of a door opening and the second plate swung from a position coplanar with the first plate to a right angle position to overlie the marginal face portion of a door when closed. The second plate mounts a bolt for sliding movement in a direction normal to the hinge axis, the hinge shaft having a receiving bore for receiving the bolt when the first and second plates are at right angles to thus lock the plates in right angle relationship. The door is thus secured against opening. The same arrangement may be utilized for hinge mounting cabinet doors wherein the hinge lock serves the dual function of a hinge as well as a lock.