The ostomy receiving bag comprises a front wall (2) and a rear wall and has a top end and a bottom end. The top end of the rear wall is provided with an inlet to receive a stoma, and one wall is provided with at least one first half of a fixation pair (A), and the same effective wall after closure of the bag, if available, is provided with at least one second half of a fixation pair (B), such that when the first half and the second half of the fixation pair are attached, the volume of the receiving bag is reduced.