A catalytic flat plate fuel reformer offers better heat integration by combining the exothermic catalytic combustion reaction on one side and the endothermic catalytic reforming reaction on the other side. In this study, steam reforming of natural gas (methane) coupled with a methane catalytic combustion in a catalytic flat plate reformer is studied using a two-dimensional model for a cocurrent flow arrangement. The two-dimensional computational fluid dynamics (CFD) model makes the predictions more realistic by increasing its capability to capture the effect of various design parameters and eliminates the uncertainties introduced by heat and mass transfer coefficients used in one-dimensional models. In our work we simulated the entire catalytic flat plate reformer (both reforming side and combustion side) and carried-out studies related to important design parameters such as channel height, inlet fuel velocities, and catalyst layer thickness that can provide guidance for the practical implementation of such fuel reformer design. The simulated transverse temperature profiles (not shown here due to page limitation) show that there is virtually no heat loss across the plate at the reformer exit. Introduction of a water gas shift (WGS) reaction at the reformer side along with our optimized reformer design parameters decreases the amount of carbon monoxide (CO) almost 90%–98% in the final reformate exiting the reformer as compared to without the WGS reaction. The CFD results obtained in this study will be very helpful to understand the optimization of design parameters to build a first generation prototype.