Aligned carbon nanofibers/tubes, ca. 20-50 nm in diameter, were generated by hollow cathode glow discharge decomposition of Fe(C5H5)(2) in He at ca. 200 degreesC on an Al2O3 membrane. The as-deposited product consists of bundles of amorphous carbon nanofibers with numerous Fe nanoparticles embedded therein. Heating at 1100 degreesC under Ar produced well-crystallized carbon nanotubes.