The chemisorption of CO on Ni(110) has been studied at temperatures down to −145 °C, by means of LEED, Auger and work function measurements, and flash desorption. Since electron impact caused dissociation of the adsorbed molecules, precautions had to be taken to minimize spurious effects. The LEED patterns showed considerable disorder but could be described approximately by the sequencec(2×2)→(4×2)→c(2×1). These structures suggest that both linear and bridged bonding of CO occurs on Ni(110), and flash desorption revealed two bindings states separated by ∼0.2 eV. The isosteric heat of adsorption for the lower energy state was found to be 1.1 eV. The maximum work function change was 1.6 eV.