We report a new fabrication method for the production of ultrathin Nb nanopin arrays on Si substrates using an anodic aluminum oxide nanotemplate combined with wet etching techniques. Each Nb nanopin in the nanopin array has a tip diameter of several nanometers, which was confirmed by tunneling electron microscopy and energy-dispersive spectrometry. The ultrathin Nb nanopins used as electron beam sources exhibit a field-emission current and emission site density higher than seen in previous results. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3532942] All rights reserved.