Adsorption of cyclooctyne on Si(001) was investigated by means of scanning tunneling microscopy. Two different adsorption configurations were identified for the chemisorbed molecules which exhibit a tendency for clustering along the dimer rows. At high coverage well ordered adsorbate structures are formed. The adsorption behavior was observed to be similar at room temperature and at low surface temperature of 50 K. Moreover, it was found to be insensitive to distorted, hydrogen induced dangling-bond configurations. Our results suggest a direct adsorption pathway for cyclooctyne on Si(001) most likely governed by the molecule's triple bond in combination with its high ringstrain. (C) 2012 Elsevier B. V. All rights reserved.