Nanostructured titanates with different morphologies such as nanoflakes, nanotubes, and nanofibers have been selectively synthesized by a simple solvothermal treatment of commercial anatase TiO2 using the mixed water-ethanol cosolvent at low alkaline concentration. The effects of solvothermal temperature, volume ratio of H2O to C2H5OH, amount of NaOH and solvents on the formation of titanate nanostructures have been systematically studied through X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). At low concentration of NaOH solution (the actual concentration of OH- in the solution is only 0.58 M), different titanate nanostructures are achieved by simply changing the volume ratio of H2O to C2H5OH at 180 A degrees C and titanate nanotubes can be synthesized between 100 and 180 A degrees C. A probable formation mechanism is proposed based on XRD, SEM and TEM analysis. The influence of cosolvent on the transformation from anatase TiO2 to titanate is also investigated.