The electrical, optical, and various mechanical properties of rf sputtered indium tin oxide layers were investigated in terms of electrical resistivity (four-probe measurement and Hall), optical transparency, scanning transmission electron spectroscopy and x-ray spectroscopy. Whereas the specific conductivity is. at the lower limit reported in the literature (2 X 10(-4) Omega cm), and the optical transparency is as high as 90% in the wavelength range between 550 and 800 nm, the grain size is between 10 and 25 nm. The stress is tensile and in the range of 7 kbar after deposition, to drop to 3 kbar after anneal.