A mail drop box for isolating mail deposited therein having a closable, removable container inside the box for receiving mail and has an opening in the top. A plurality of mail transmitting chutes each having a deposit port at its upper end and an exit port at its lower end to receive mail through the deposit port and direct such mail into the container. The opening in the removable container is closed when desired to isolate mail from the ambient atmosphere and permit removal of the container without exposing the ambient atmosphere to hazardous particles which may be on or in such mail. A removal door permits removal of the container. A transparent door is adjacent to, but inside of, the removal door for allowing viewing of the opening of the container when the removal door is open.