The structure and electrochemical behavior of vanadium-modified olivine LiFePO4 was investigated. Vanadium was found to be incorporated into the olivine structure on the phosphorus site, not on the iron site, with the unit cell decreasing in size as the vanadium content increases. Material synthesized under reducing conditions with 5% vanadium gave materials with the best electrochemical performance. The rate capability of nanostructured LiFeP0.95V0.05O4 was comparable to the best nanosized LiFePO4 formed solvothermally while using less than 1/3 the amount of carbon conductor. The vanadium does not appear to be electrochemically active within the voltage cycling window of LiFePO4.