The surface and bucking instabilities of vertical well-aligned aluminum doped ZnO nanorods on the lime-glass substrates prepared using the sol-gel method are characterized by nanoindentation tests. Comprehensive structural analysis by X-ray diffraction and scanning electron microscopy reveal that the ZnO nanorods are grown as a single crystal along the [0 0 2] direction without any dislocation. Uniaxial compression tests of individual nanorods with the Berkovich and a conical indenter and of group of nanorods with flat punch indenter have been carried out. Using the Euler buckling model, the elastic moduli of ZnO nanorods using these three different indenters are within the range of 175-256 GPa. We discuss the relative merits of these two approaches for the determination of the elastic properties of ZnO nanorods, particularly considering the difference and difficulties of each approach. The ZnO nanorods prepared by the sol-gel method are mechanically strong and may assist the development of the applications of one dimensional nanorods. (C) 2012 Elsevier B.V. All rights reserved.