Particular reaction steps of the partial oxidation of methane to synthesis gas over Pt/MgO, i.e. methane dissociation, CO2 adsorption, CO adsorption and oxidation, were studied under reduced pressure in the temporal-analysis-of-product-(TAP) reactor. Kinetic rate equations and parameters were derived which led to adequate description of experimental data. Methane dissociation occurs on partly reduced metal sites and is related to a cooperative effect of surface oxygen. CO2 adsorption proceeds via a weakly bonded precursor which is consequently transformed into carbonate and bicarbonate species. CO oxidation probably takes place on oxygen islands of the platinum surface. Two different adsorption states of CO seem to be relevant under reaction conditions. The applicability of kinetic parameters obtained from the transient studies to steady-state conditions is discussed.