We report the observation of temperature dependent tunneling behavior of capillary tunnel junctions of octadecanol (C18H37OH) from room temperature to 130 degreesC. The molecular tunnel junction consists of octadecanol (C18H37OH) sandwiched between tin electrodes utilizing the naturally existing surface oxides. The resistance of the molecular junction was found to increase appreciably at temperatures around 80 degreesC. The transition of the junction resistance is suggested to be associated with the breaking of hydrogen bonding between molecular terminal groups with the electrode surface. (C) 2003 Elsevier B.V. All rights reserved.