In this work it was determined the necessary anodic recirculation ratio that maximizes the hydrogen production for a process integrated by a solid oxide fuel cell (SOFC) and a micro-reformer fed with biogas. For this purpose, a thermodynamic study was made of the recirculation effects over: a) the ratio of reforming agents/methane, b) the outlet/inlet atomic hydrogen ratio (ψ), c) the reactor relative size, and d) the normalized electric energy output. The results show that in order to avoid coking, a steam-to-carbon ratio (S/C) higher than 2 is unnecessary, for a combined reforming with steam and CO2. Moreover, it was found that ψ is maximized at a recirculation ratio of 0.22; and that an increase of recirculation caused a decrease in the electrical energy produced, and an increase in the relative reactor volume. Finally, it was found that a recirculation ratio of 0.22 was the best option for an operating temperature of 850°C. If the recirculation ratio is exceeded to achieve S/C= 2, the hydrogen fraction produced will decrease 50% and the reactor volume will increase 118% for the same amount of biogas fed.