Self-ordered arrays of titanium oxide nanotubes were prepared by anodization of Ti in sodium sulphate solution containing sodium fluoride. The dimensions of the nanotubes (diameter: 20-100 nm and length: 1000-1500 nm) could be tuned by changing the synthesis parameters. The as-anodized nanotubes showed amorphous structure which upon annealing at 500{ring operator}C in oxygen atmosphere turned crystalline, according to XRD analysis. The pit morphologies show that pit initiation occurs due to NaF content in the electrolyte and nanotube formation starts after pit growth terminates. © 2012 American Institute of Physics.