This paper reports the state of art on fuel cells technology, outlines the most significant results reached all over the world and summarises the strategies developed by researchers and producers to get the commercialisation of these systems. In particular, the authors have examined three potential application fields for fuel cells: (i) stationary power plant for electricity production; (ii) portable power applications; (iii) electric vehicles. The potential market area for each sector of application has been defined and the research activity necessary to overcome the technical problems that are still open have been detailed. The significant projects of main fuel cells producers are also mentioned.