Indium-tin oxide films have been deposited by reactive electron beam evaporation of In+Sn alloy both in neutral and ionized oxygen environments. A low-energy ion source (fabricated in-house) has been used. Films deposited with neutral oxygen exhibited very low optical transmittance (5% at 550 nm). Highly transparent (85%) and low-resistivity (5×10–4 cm) films have been deposited in ionized oxygen at ambient substrate temperature. Optical and electrical properties of the films have been studied as a function of deposition parameters.