Abstract: A urine bag, which is folded flat so that it is compact and ready for use, has a water impermeable bag portion and a flexible mouse portion secured at an upper opening of the bag portion. The flexible mouse portion surrounds at least a portion of the upper opening of the mouse portion and has shape preserving capability. The mouse portion includes left and right wings which can be displaced around a first central folding line to open or close the upper opening, and left and right tongues. The tongues can be displaced together with the wings around a second central folding line which is an extension of the first central folding line. The mouse portion also has a pair of symmetrical folding lines extending diagonally from the intersection of the contour of tongues and the upper edges of the wings to the first central folding line.