The present work demonstrates that morphology of TiO2-WO3 composite nanotubes formed by alloy anodization can be tuned by controlling applied voltages and time. Distinctive tube morphology can be formed by applying a voltage of more than 80 V. Nanotube diameter and length have a linear relationship with the anodization voltage with a current efficiency of almost 100 %. Furthermore, compared to pure TiO2, the composite nanotubes show a very uniform tube diameter along the tube axis even at the extended anodization time.