Oriented SnO2nanowire (NW) arrays were grown on TiO2(001) substrates by molecule-based chemical vapor deposition of Sn(OtBu)4. Preferred growth directions ([101], [-101], [011], and [0-11]) of SnO2NWs were correlated to surface energy consideration and crystallographic relationship between the substrate and NW material by comprehensive electron microscopy and bulk tomographic studies. The proposed growth incubation model (tilting of catalyst/NW interface due to driving force of surface energy) explains the formation mechanism of oriented SnO2NWs on TiO2substrates. These results allowed us to also study the I-V characteristics and gas-sensing properties of individual SnO2NWs grown with a perfectly defined crystal orientation ([101]).