We have studied the effect of oxygen plasma treatment on piezoelectric response and on the mechanical stability of ZnO nanorods synthesized on FTO by using ACG method. XRD and SEM techniques have shown highly dense and uniformly distributed nanorods. The piezoelectric properties and mechanical stability of as-grown and oxygen plasma treated samples were investigated by using nanoindentation technique. The comparison of load-displacement curves showed that the oxygen plasma treated samples are much stiffer and show higher generated piezo-voltage. This study demonstrates that the oxygen-plasma treatment is a good option to fabricate reliable and efficient nanodevices for enhanced generation of piezoelectricity. (C) 2014 Elsevier B.V. All rights reserved.