Abstract: An ostomy pouch and high-performance gas filter assembly therefor, in which the filter assembly includes an envelope defining a filter chamber containing a radial flow deodorizing filter pad. The pad's opposite faces are joined to the inner surfaces of the envelope in such a way that the periphery of the pad is fully exposed within the chamber. A first passage extends through the filter and communicates with a first opening in a wall of the envelope over which a first microporous membrane extends. A second opening extends trough the opposite wall of the envelope at a distance spaced laterally from the first opening, and a second hydrophobic microporous membrane extends over the second opening. In a preferred embodiment, the filter pad is oblong in shape and has a second passage spaced laterally from the first passage and communicating with the second aperture.