Single-crystalline nanoporous Nb₂O₅ nanotubes were fabricated by a two-step solution route, the growth of uniform single-crystalline Nb₂O₅ nanorods and the following ion-assisted selective dissolution along the [001] direction. Nb₂O₅ tubular structure was created by preferentially etching (001) crystallographic planes, which has a nearly homogeneous diameter and length. Dense nanopores with the diameters of several nanometers were created on the shell of Nb₂O₅ tubular structures, which can also retain the crystallographic orientation of Nb₂O₅ precursor nanorods. The present chemical etching strategy is versatile and can be extended to different-sized nanorod precursors. Furthermore, these as-obtained nanorod precursors and nanotube products can also be used as template for the fabrication of 1 D nanostructured niobates, such as LiNbO₃, NaNbO₃, and KNbO₃.