Nb doped SrTiO3 (Nb: STO) films were deposited on (100) SrTiO3 substrates using a pulse laser deposition technique. The effects of deposition pressure on their structural, electrical and optical properties were investigated. Decrease in deposition pressure lead to decrease in grain size and average surface roughness. Various optical parameters such as refractive index, extinction coefficient, and band gap were calculated by applying the envelop or extrapolation methods using the transmittance data obtained from a UV/Vis spectrophotometer. A systematic decrease in resistivity and increment of negative charged carriers was observed with decreasing deposition pressure. Experimental results exhibited electro- and opto-resistive switching behaviors with a resistive transition from high resistance state to low resistance state on the application of current-pulse or UV light. Multi-level resistance states have also been demonstrated using a train of current pulses of different magnitudes or a simultaneous application of current and UV light. Such observed phenomenon makes Nb: STO a potential candidate to be used in future for the fabrication of multi-level memory devices and transparent thin films transistors. (C) 2012 Elsevier B. V. All rights reserved.