Various silver and cerium exchanged zeolites were screened on their activity in the reduction of NO, with propene under lean burn conditions. Furthermore, the performance of co-exchanged Ag-Ce-H-BEA (beta) and Ag-Ce-H-FER (ferrierite) for this reaction was studied. The catalysts were tested in a simulated exhaust gas mixture, composed of 400 ppmv of NOx 400 ppmv of propene, 10 vol.% of oxygen, 10 vol.% of water and balance nitrogen, at a space velocity of 47 700 h(-1). The NOx conversion of the silver exchanged zeolites was ranked as Ag-Na-BEA > Ag-H-FER, Ag-H-BEA, Ag-K-FER > Ag-H-ZSM-5. Ag-Na-BEA showed 42% NOx conversion at 300degreesC. The NOx conversion of the cerium exchanged zeolites decreased in the order of Ce-H-FER > Ce-H-ZSM-5 > Ce-H-BEA. Ce(75)-H-FER showed 90% NOx reduction at 350 degreesC, which is high, also in comparison to Ag-H-FER, Pt-H-FER, Cu-H-FER and Co-H-FER. The NOx reduction over Ce-H-FER was above 40% in the temperature range of 300-500 degreesC. No synergetic effect on the NOx reduction activity with propene was observed for the co-exchange of silver and cerium in H-ferrierite.