Abstract: A portable door lock and alarm is adapted to connected to the hinge carried between a door and a doorjamb. The portable door lock and alarm provides an enclosure housing a lock mechanism which includes a claw defining small and large hinge passages adapted to surround small or large door hinges. A bolt, extending from the claw and through the enclosure, is threaded onto a knob. After attachment of the claw to the hinge, rotation of the knob retracts the claw into the enclosure, increasing the pressure between the door and doorjamb and the enclosure. An attempt to open the door will increase the pressure on the enclosure; however, in a typical application, the door will crack, break or deform before the enclosure of the lock is crumpled. A circuit provides a switch that is closed if an attempt is made to open the door, thereby resulting in activation of an annunciator.