Free-standing lithium niobate nanowires (LiNbO3) are synthesized by the hydrothermal route. The polarization response of the second harmonic generation (SHG) signal is measured in a single nanowire and used to identify the crystal orientation by matching with bulk LiNbO3 nonlinear optical susceptibility. The electrical manipulation of a LiNbO3 nanowire and its monitoring through the SHG signal in a fluidic setup are demonstrated. © 2009 American Institute of Physics.