Oxidative coupling is not yet competitive for converting methane to liquid fuels. The process is extremely exothermic and is strongly influenced by reaction selectivity. The methane coupling reactor system, which must operate at high temperature, is the primary contributor to the high cost of the oxidative coupling process. This paper investigates two systems—the multitubular reactor and the fluidized bed reactor—for their feasibility and cost effectiveness. A multitubular reactor of impractical dimensions would be required to control heat transfer and avoid temperature runaway. The fluidized bed reactor, however, could be feasible. Its key advantage is temperature uniformity. However, the catalyst must have stringent mechanical properties, development and scale-up of the catalyst would be complex, and piloting would be expensive. Evaluation of other approaches is needed.