Carbon nanotubes (CNTs) filled with ferromagnetic materials have the potentials for use in magnetic scanning probe microscopy and as an assembly of aligned high density magnetic nanocores for future magnetic data storage devices. Highly ordered and uniform Ni-filled CNTs were deposited by chemical vapour deposition. As-grown Ni-filled CNTs were characterized using transmission electron microscopy, Raman spectroscopy and nano-area diffraction. The magnetic properties of Ni-filled CNTs were investigated using superconducting quantum interference device analysis. Magnetisation characterization, performed at temperature 2 K with magnetic field up to 2 T, showed better ferromagnetism compared to the bulk Ni. (C) 2004 Published by Elsevier B.V.