An ostomy collecting bag is provided. The collecting bag has a continuous wall with a curvature instead of sealed edges. The collecting bag is truly three-dimensional. The collecting bag may be obtained by injection blow-moulding or extrusion blow-moulding. Methods of producing an ostomy collecting bags by either injection blow-moulding or extrusion blow-moulding is also provided. In injection blow-moulding, a pre-form is injection moulded and subsequently the pre-form is blow-moulded into an ostomy collecting bag. In extrusion blow-moulding, a tube is extruded and subsequently blow-moulded into an ostomy collecting bag. The ostomy collecting bag can thus be made without seals at the edges, which provides a more flexible collecting bag with a larger interior volume.
