Undoped and Ta-doped SnO2 (Sn1-xTaxO2) thin films were prepared on Corning 7059 glass substrates by the metal-organic chemical-vapor deposition method. The relative amount of Ta, CTa=XTa/(XTa+XSn), varied from 0 to 7.13 at. %. For the five compositions studied, the lowest resistivity at room temperature was 2.01×10-4 cm at CTa=3.75% with charge carrier density and mobility of 1.27×1021 cm-3 and 24.5 cm2/Vs, respectively. In microstructural investigation, 3.75% Ta-doped film maintains a growth pattern of initial stage growth while 7.13% Ta-doped film has a high population of small grains at the interface, which results in large grains through competitive growth. The resistivity of the undoped film was 0.17 cm with charge carrier density and mobility of 1.31×1018 cm-3 and 28.1 cm2/Vs obtained from Hall measurement. This study suggests that Ta is an excellent n-type dopant in SnO2.