NO reduction experiments were carried out in a fixed-bed reactor loaded with metal/alumina catalysts. Two hydrocarbons, methane and propene, were used as the reducing agents for the NO reduction. The former hydrocarbon exhibited relatively low NOx conversions and it was burned at high temperatures. The addition of methane to a propene-containing feed gas stream did not cause any inhibition or enhancement on the NO reduction activity over the Pt/alumina catalyst. The presence of water in the feed gas stream caused a small, reversible, inhibition effect over the Pt/, Cu/ and Ni/alumina catalysts. The maximum NO conversion was measured over Ni/alumina, followed by that over Cu/ and Pt/alumina. The peak temperature varied with the catalyst, but it was not affected by the addition of water to the feed gas stream. The presence of SO2 in the feed gas stream did not affect the NOx conversion over Pt/alumina, it caused a significant irreversible loss of activity over other metal/alumina catalysts and it enhanced the activity of Rh/alumina.