Abstract: A door safety device consists of cooperating strike plate and face plate portions corresponding respectively to the strike plate and face plate of a conventional door lock or passage set. These portions are provided with apertures which when installed at the location of the door bolt permit the passage of the door bolt therethrough; they are also provided with cooperating portions projecting into the room that with the door closed register with one another and provide registering passages for reception of a lock pin that joins them securely together. The two portions can replace the strike and face plates of an existing lock and utilize the existing recesses and screw holes so that installation is possible with only the use of a screwdriver. At least the face plate portion can be installed over the existing face plate instead of replacing it, but this usually is not preferred with the strike plate portion due to space and operating considerations.