During postulated severe accidents in nuclear power plants, Ag-zeolite filters can retain ˗among other fission products˗ iodine and organic iodides very effectively. Ag-zeolite filters are already applied in filtered containment venting systems and other nuclear power plant applications. Due to high Ag content, the filter material has a high potential to inherently recombine also hydrogen and reduce the risk of combustion and detonation in the containment atmosphere and from filtered vents. The performance of hydrogen removal from a hydrogen/air stream by two such zeolites, AgX (39% weight Ag) and AgR (11% weight Ag), was determined experimentally under expected conditions typical to severe accidents. Hydrogen recombination tests were performed at atmospheric pressure in a fixed-bed catalytic reactor with a volume of 100 cm³ at three different hydrogen contents (1.1%, 2.4% and 3.7% vol.), two preheats (120 and 140 °C) and a flow residence time of 100 ms. In all investigated AgX cases, steady-state hydrogen conversions ranged from 40.9% to 99.5% and reactor temperatures were as high as 505 °C. Post-recombination examination of the catalyst revealed strong local discoloration when the temperatures exceeded 400 °C. For all AgR cases, a much lower reactivity was observed with steady-state hydrogen conversions ranging from 1.2% to 7.0% and reactor temperatures up to 151 °C. Catalytic ignition was achieved in all cases within a few seconds, while steady state operation was reached after 4 to 5 minutes.