Minor products formed in the reaction of NO + C3H6 + O-2 over:Ga2O3-Al2O3 and In2O3-Al2O3 were identified by using GC-MS technique. A lot of minor products, such as oxygenated, nitrile, nitrite compounds and higher hydrocarbons were detected on both catalysts. The formation of surface nitrile species in the NO + C3H6 + O-2 reaction was also recognized in the diffuse reflectance FT-IR spectra. FT-IR spectra showed that the reaction starts with the formation of adsorbed nitrate (NO3-) species via NO oxidation by O-2. From the comparison of the distribution of minor products in NO + C3H6 + O-2 and 2-nitropropane oxidation, a reaction pathway in which NO reduction proceeds through the formation of organic nitro compounds and subsequent decomposition to some oxygenated and nitrile compounds was proposed.