Abstract: A multiwall cooler bag is formed by gusseted inner and outer tubes, the outer tube being made of kraft paper and having its lower end circumferentially bonded to the inner tube, the inner tube comprising an inner ply of plastic material heat sealed to closure at its lower end and an outer ply of kraft paper, with a strip of plastic reinforcing material extending the length of and secured to the back and front walls of the outer tube. The front wall of the outer tube has its lower end formed with a closure flap secured to the back wall of the outer tube, while the back wall of the outer tube has its upper end formed with a closure flap overlapping the front wall when the bag is completely closed. The upper portion of the inner tube is free of the outer tube to permit independent closing of the inner tube before closing the outer tube.