The aim of this research work is to describe in qualitative and quantitative form the performance of a micro Combined Heat and Power system for residential application based on Solid Oxide Fuel Cell fueled by natural gas with two different types of pre-reforming systems, namely Steam Reforming and Partial Oxidation and recirculation of anode and cathode gas. The comparative analysis among the different configurations will lead us to conclude that maximum efficiency is achieved when cathode and anode gas recirculation are used along with steam methane reforming. Further Steam Methane Reforming process produces a higher electrical system efficiency compared to Partial oxidation reforming process. Efficiency is affected when running the system in part load mode mainly due to heat loss, additional natural gas supplied to the burner to satisfy the required heat demand inside the system, and ejector efficiency drop in the recirculation system. Due to high temperature of operation heat loss strongly affects the system efficiency especially at part load operation. (C) 2011 Elsevier Ltd. All rights reserved.