Scanning Tunneling Microscopy and Spectroscopy investigations have been carried out on electron beam deposited indium tin oxide films. The STM images reveal a rather smooth surface, which appears to have been formed due to the coalescence of islands with different shapes. The spectroscopic data, in general, exhibit characteristics typical of metal-insulator-semiconductor structures, with a heavily doped semiconductor. From the I-V curves, a band gap of ≈3.5 eV is obtained, which is very close to the bulk value. The I-V studies at some grain boundary interfaces suggest the presence of regions showing electronic characteristics, that differ significantly from what is observed on the rest of the film surface. © 1997 Elsevier Science Ltd. All rights reserved.