We have studied the surface dynamics of a double-strand decanucleotide (HS-10AT L) with 10 adenine–thymine base pairs linked to a Au(1 1 1)-electrode surface via a hexamethylene thiol linker. The study is based on a combination of voltammetry, interfacial capacitance data, electrochemical in situ scanning tunnelling microscopy, and X-ray photoelectron spectroscopy. The thymine bases of the oligonucleotide are connected to furanoses locked in a C3′- endo configuration called LNA (locked nucleic acid). Hybridization in solution is effected prior to linking to the Au(1 1 1)-surface. The melting point of the linker-free locked decanucleotide, 10AT L is >63 °C. However, voltammetric reductive desorption of the adsorbed thiol-modified double-strand decanucleotide, HS-10AT L, gives almost the same charge as single-strand HS-10A, 29 ± 3 and 27 ± 5 μC cm −2, respectively. In situ STM after HS-10AT L-immobilization also gives images showing highly ordered domains, virtually indistinguishable from those of immobilized HS-10A. X-ray photoelectron spectroscopy gives an N/P ration of 5.0 for HS-10AT L in line with the expected value for single-strand HS-10A (5.0). All three sets of data suggest that HS-10AT L hybridized in solution is significantly dissociated on binding to the Au(1 1 1)-electrode surface. This points to an adsorption mechanism in which a stable high density of Au–S bonds is achieved but at the expense of significant unzipping of the more voluminous duplex form.