The disclosed disposable vacuum cleaner has a disposable bag with a collar at the bottom, rather than on the sides. Dirty air enters the bag vertically, rather than horizontally, through a duct that is positioned near the floor, separate from the handle on the vacuum cleaner. An elongated, light-weight tube is disposed within the bag, and has a lower end that is connected to the collar. The tube is made of a thin, lightweight, lay-flat tubing with opposed creases, and is flexible and collapsible. It has a length that is greater than half the height of the sides of the bag. The collar has a seal that is trapped between two pieces of mounting material and extends around the periphery of the duct, providing an elastic seal. The bag has a top that is reinforced with a cardboard support. Extending flanges on the support can be used to suspend the bag from arms in the vacuum cleaner.