In a catalysts screening for the nitrous oxide decomposition, three groups of catalysts (metals on supports, hydrotalcites, and perovskites) were studied relating to their activity in the presence of vapor or sulfur dioxide, in the temperature range from 200 to 500 °C. It was found that the water vapor strongly inhibates the nitrous oxide decomposition at T = 200-400 °C. The sulfur dioxide poisons the catalysts, in particular the perovskites. The catalysts Rh-ZrO₂ and Ex-Co, Rh-Al-HTlc are potentially suitable for the nitrous oxide decomposition in exhaust gas at around T = 500 °C.