A hydrocarbon fuel composition which is suitable for sue in a fuel cell apparatus and an internal combustion engine comprises at least one saturated aliphatic hydrocarbon having 4 to 12 carbon atoms, and is characterised by an olefin content of less than 20% by volume, an aromatics content of less than 42% by volume, a final boiling point (fop) of less than 215° C., and a sulphur content of less than 20 ppm.