Abstract: An apparatus for preventing a door from opening. The apparatus preferably comprises a pair of anchors which are mounted to a floor. The anchors are located beyond both edges of the door on the side toward which the door opens. Each of the anchors has a slot in it so that it can accept an end of a cross bar to form a connection. The anchors are oriented so that the slot in each anchor aligns with the slot in the other anchor when the door is in a closed position and the apparatus is engaged. A cross bar is placed between the anchors to prevent the door from opening. The cross bar is connected to the anchor on the edge of the door which is on the same edge of the door as the hinge of the door by a pin which allows the cross bar to be rotated upwardly. The anchor with the hinge is connected to the floor in such a manner as to allow the anchor to rotate on an axis which is perpendicular to the floor.