[100]Oriented SnO2 thin films were obtained on glass substrates from di-n-butyltin(IV) diacetate at 480 degreesC by a spray pyrolysis deposition technique. The thermal decomposition processes of the starting materials were studied by vapor pressure measurement, gas chromatography, and mass spectroscopy for the elucidation of the formation mechanism of the films. Consequently, a growth model concerning the [100]-oriented SnO2 thin films was proposed on the basis of crystallographic considerations, in which the chemical species O-Sn-O appears to be the pyrolytic product of the starting material.