Nowadays, the development of new green technologies has been promoted worldwide both by public and private institutions. In this context the research on microbial fuel cells (MFC) represents a promising alternative to carbon based energy sources. Unfortunately, this technology has been always affected by too low current density output for allowing an intensive application in the industrial and civil field. The study deals with this limitation and focuses on the implementation of metallic sponges, specifically cast iron based, as electrodes, aiming at increasing the exposed surface and thus the current density at the MFC anode. Cast iron was selected because of its low toxicity for the microorganisms, however its high melting point carries several problems for the manufacture process. Parallel to this, the realization of electrodes using foamed metals implies further issues related to the generation of correct pore size distribution and adequate bacterial activity. For instance, the metal foams are expected to be open-cell type, so that there can be an efficient mass transport also to the inner regions of the electrode. In order to control these parameters the metal sponges are produced by infiltration of cast iron on ceramic beds. Combining previous data with the measurements of power generation efficiency the authors conclude the study attempting to design MFCs with metal foamed electrodes.