An opening and closing mechanism for a roll-up cargo door for a truck is intended to decrease injuries to the people who load and unload items from box trucks and semi-trailers. The mechanism allows the user to open and close the overhead roll-up door of these trucks while standing firmly and safely on the ground at the rear corner of the truck. The door opening and closing mechanism is in the form of a loop of material that is attached to a lower portion of the roll-up door and a guide disposed near the top of the door frame. The loop is disposed along one of the vertical frame members of the door so that it is out of the way of the cargo hold when the door is open.