Abstract: A panic exit door locking mechanism adapted particularly for mounting on a narrow stile door frame, and which includes top and bottom bolt mechanisms respectively at the upper and lower ends of the tubular frame at the swinging edge of the door, the locking instrumentalities including a rotatable lever arrangement concealed within the tubular stile, and being connected to the bolt mechanisms by concealed rod structures that are length adjustable for doors of different heights. Actuators for the rotatable lever arrangement comprise a manually operable panic exit actuator device mounted on the inner side of the door and/or a conventional key-controlled rotatable cam lever having a lost motion relation with the rotatable lever arrangement.