The adsorption, thermal reactions, and photochemistry of methylamine on TiO2 have been investigated using infrared spectroscopy. It is found that methylamine is adsorbed molecularly on TiO2 at 35 degreesC. Hydrogen exchange occurs between the NH2 group of adsorbed methylamine and surface OH groups. Thermal reactivity of methylamine is enhanced in the presence of O-2, producing NH3(g), CO2(g), and other oxygenated compounds. UV irradiation of TiO2 in the presence of methylamine and oxygen generates NH3(g), CO2(g), H2O(g); NCO(a), and HCOO(a). Possible reaction steps for the photoproducts are discussed.