Vapour-grown carbon fibres (VGCF) were produced from a methane-hydrogen mixture on a substrate seeded with an iron catalyst. The influence of the operating conditions and of the nature of the catalyst precursor on the yield and properties of the VGCF produced was investigated. The presence of hydrocarbon during the catalyst reduction stage and the heating rate imposed during the fibre growth step were found to be the most important factors determining the yield of VGCF, while Fe-3(CO)(12) proved to be an excellent precursor, producing the longest fibres.