The catalytic properties of cobalt containing ZSM-5 zeolites prepared by various methods were compared. TPR, XRD, N-2-BET, XPS, FTIR and W-vis spectroscopy were used for characterizing the samples. Well-dispersed cobalt oxide-like species and isolated Co2+ ions in charge compensation positions were found in the zeolite. Catalysts prepared using a single step cation exchange method showed high activity for N2O decomposition in a temperature range 300-550 degrees C, in the presence of 0-5% O-2, and high stability in the presence of 10% H2O to the feed. UV-vis spectra and TPR experiments indicated the presence of some cobalt oxides, not detected by DRX, in a Co-ZSM-5 catalyst containing 3.76 wt% Co, prepared by a solid-state reaction procedure. The N2O conversion over this catalyst was strongly affected by addition of both O-2 and H2O to the feed.