The effect of oxygen flow rate on the electrical and optical characteristics of dopantless tin oxide films prepared by low pressure chemical vapor deposition (LPCVD) was investigated. A decrease in the sheet resistance of the film with increasing oxygen flow rate in the range of 200-300 sccm was attributed to an increase in the film thickness (and correspondingly, in the grain size); while at oxygen flow rates higher than 300 sccm, the increase in the sheet resistance of the film resulted from an increase in the X-ray diffraction peak intensities of the (110), (101), and (201) planes. The optical bandgap of the film decreased when the oxygen flow rate was increased from 200 to 300 sccm, but it remained nearly constant for oxygen flow rates higher than 300 sccm. A maximum figure-of-merit was achieved for films prepared with an oxygen flow rate of 300 sccm.