Heterogeneous ignition and steady-state kinetics of reaction between methylamine and excess oxygen on polycrystalline platinum have been studied in a mixed reactor. The oxidation of hydrogen initiates the ignition, and the released heat which increases the temperature of platinum wire accelerates the decomposition of methylamine, and then more hydrogen is released until a final steady-state of the system is reached. CH3NH2 --> HCN + 2H(2), 2H(2) + O-2 --> 2H(2)O, and HCN + 7/4 O-2 --> NO + CO2 + 1/2 H2O, are the reactions which react when a mixture of methylamine and oxygen contacts a high-temperature Pt wire. The flux limited kinetics of these three reactions can be described by Langmuir-Hinshelwood (LH) rate expressions with empirical expressions for the sticking coefficients. It is found that these Langmuir-Hinshelwood rate expressions correlate all rate data within +/-15% at all temperatures and pressures. The results suggest that the reactive species are strongly inhibited by molecular oxygen. The selectivities of products can be quantitatively determined.