Oxidative steam reforming (OSR) of methane is investigated under exhaust gas reforming conditions in a wall-coated catalytic microchannel reactor. The process is run over different combinations of Pt- and Rh-based catalysts, namely 0.2% (by weight) Pt/Al2O3-2%Rh/Al2O3, 2%Pt/Al2O3-2%Rh/Al2O3, and 2%Rh/Al2O3-2%Rh/Al2O3. In each combination, coated catalysts are locked on the opposite walls of a rectangular microchannel to face each other. Parametric study is conducted in order to observe the effects of feed compositions (molar steam-to-carbon (H2O/C) and oxygen-to-carbon (O-2/C) ratios) and temperature on methane conversion and on product distribution. The results show that methane conversion is enhanced with the increase in temperature and in the amounts of O-2 and H2O in the feed stream. When the temperature is raised from 600 to 700 degrees C, methane conversion is found to improve by ca. 25% in all catalyst configurations. Increasing H2O/C and O-2/C ratios improved methane conversion at most by 7% and by 23%, respectively. H-2 production also increased with temperature, with the highest increase of 5% is observed over the 2%Rh/Al2O3-2%Rh/Al2O3 combination. Higher O-2/C ratios improved the extent of methane total oxidation but decreased H-2 production. The catalyst combination involving 2% Rh/Al2O3 coated oppositely onto the inner walls of the microchannel is found to exhibit the best performance in terms of methane conversion and H-2 and CO amounts in the product stream. A 10% increase in methane conversion is observed either by changing the Pt content from 0.2% to 2% or by replacing 2%Pt with 2%Rh. The results show that Rh is superior to Pt in terms of oxidation and steam reforming activities.