An ostomy bag (1) with a filter construction with an intermediate filter element (4) is provided. The intermediate filter element comprises a first wall (5) and a second wall (6) that, when the filter construction is positioned in the ostomy bag, is substantially parallel to the front and rear wall of the ostomy bag. The walls of the intermediate filter element include the gas-inlets for the filter construction. The intermediate filter element may be provided so that it constitutes an insert interposed between the rear wall and the front wall of the ostomy bag. The intermediate filter element may also be provided so that it constitutes a tube element.