We report on the synthesis and characterization of nanofibrous structures of vanadium oxide V2O5 by anodic electrodeposition. The electrodeposits are thick layers of several micrometers consisting of fibers with length in the micrometer range and a width of about 10 nm. At variance with available reports, the vanadium oxide nanofibers were obtained without the use of templates or additives. Electrochemical synthesis was performed in aqueous solutions containing VOSO4 and Na2SO4. The observed spongelike structure, and consequent large surface area, with strong entanglement of the nanofibers are potentially important material features for applications such as gas sensors, lithium batteries, and catalysis. (c) 2007 The Electrochemical Society.