Abstract. Effects of annealing and lm thickness on the electrical and optical properties of Sb:SnO2 fi lms deposited by electron beam from bulk samples prepared using sintering technique have been investigated. A compromise between low resistivity and high transparency of the lm has been studied using the factor of merit. This factor, which has been found maximum for lm 100 nm thick annealed at 550 oC for 15 min, seemed to be enhanced with increasing annealing time and/or lm thickness con rming the simultaneous improvements of transparency and conductance with the latters. Other optical and electrical parameters such as refractive index, width of energy gap, density of localized states, concentration and mobility of carriers and Seebeck coecient have been studied also, discussed and correlated to the microstructure changes with annealing and lm thickness