Electrochemical etching in an aqueous solution (NaOH, HCl), using a teflon tubing to physically restrict the active etching region, has been developed to fabricate Scanning Tunneling Microscopy (STM) tips from a range of magnetic materials. Tips have been produced from polycrystalline MnNi, Cr, Fe and Ni with small radius of curvature, high aspect ratio and apexes in the 50–100 nm range. Atomic resolution STM images have been achieved on the Fe3O4(001) and (111) surface using MnNi tips, which are interpreted in terms of a possible spin‐polarized effect. © 2003 American Institute of Physics