We have developed a simple one-step template-free method for the controlled synthesis of hollow or hollow core/shell-type SnO2 nanostructures with controllable sizes in the range of 200 – 500 nm. This method is based on hydrothermal treatment of stannate in a mixed ethanol-water solvent. An inside-out Ostwald ripening mechanism is proposed to account for the template-free formation of these hollow nanostructures. With the addition of urea or thiourea, the current method is suitable for inexpensive, mass production of SnO2 hollow nanoparticles. A shortcoming of the method is that size uniformity of the as-synthesized SnO2 hollow nanoparticles is difficult to achieve. To solve this problem, the hydrothermal method has been extended to synthesize SnO2 hollow nanostructures with controlled sizes using monodisperse silica nanospheres as templates. Remarkably, uniform surface coating can be achieved without any prior surface modification. By repeated hydrothermal deposition or controlling the synthetic conditions, multi-shelled structures can also be prepared. We further demonstrate that functional cores (e.g. Au, magnetic particles) can be introduced into these polycrystalline SnO2 nano-containers. Lastly we demonstrate that non-spherical hollow SnO2 nanostructures can be synthesized by selecting non-spherical particles as templates. These hollow SnO2 nanostructures may find applications in many important technological fields. Here we study their application as electrodes for lithium ion batteries and report encouraging initial results.