Indium-doped ZnO nanospirals were synthesized by one-step thermal evaporation. Transmission electron micrographs show that the nanospirals are structurally uniform and free of defects. The helical nanostructures, which are constructed by rolling nanobelts grown along the < 10 (1) over bar0 > direction with the +/-(0001) polar planes as the dominate surfaces, are energetically favored in terms of the electrostatic polar charge model. The typical radius of curvature of the nanospirals is several micrometers. The In-doped nanospirals are expected to have interesting optoelectronic and mechanical properties and could be potential building blocks in nanoscale optoelectronic and electromechanical systems. (C) 2008 American Vacuum Society.