A process to desulfurize a fuel gas, such as natural gas, for use as a feed fuel for a fuel cell is characterized by providing a feed stream (10) of sulfur containing gas, passing part of that as a stream (12) to a compressor (14), passing the compressed stream to a sulfur selective membrane (16) to provide a sulfur rich stream (18) which is returned to the feed stream (10), and a sulfur lean stream (20) which can be passed to an optional gas meter (26) and then to a sulfur sorbent medium (28) before reforming the essentially sulfur free stream (34) in the reformer (40) of a fuel cell unit (36) also containing a fuel cell (38).