Two morphologies of nanostructured tin dioxide (SnO2) (i.e., nanobelts and nanowires) were compressed in diamond anvil cells up to 38 GPa followed by decompression. In situ Raman spectroscopy and synchrotron X-ray diffraction were employed to monitor the structural transformations. It was found that nanostructured SnO2 behaved drastically differently than bulk material in terms of transformation pressures, phase stability regions and compressibility. These findings provide new insight into the unique pressure behaviours of nanostructured materials and have profound implications for producing controlled structures with new applications achieved by combined pressure-morphology tuning. (C) 2009 Elsevier B.V. All rights reserved.