Abstract: A storage bag for a pickup truck provides a convenient way for people to use the bed of their pickup truck to store possessions. The storage bag is in the shape of the truck bed. The bag is preferably lightweight and waterproof. The bag is constructed from one piece of nylon to help eliminate seams, which aids in weatherproofing. A zipper extends around the top surface of the bag to aid in the opening, closing, and packing of the bag. There is also a zippered flap on the end so that cargo can be stored or retrieved by opening the hinged gate of the truck bed. The bag optionally has waterproof pockets for smaller items. Grommets are provided on an upper surface of the bag for securing the bag to the truck with rope, bungee cords, or the like. The storage bag stands alone and retains its shape without the aid of the truck. When the storage bag is empty, it is easily collapsed and folded for storage.