A speciation method for vanadium(IV) and vanadium(V) is presented that uses a combination of HPLC and ICP-AES. In this method, 1 mM HNO₃ solution and 100 mM HNO₃ solution were applied in sequence as eluent. A vanadium(IV) and vanadium(V) mixture was injected into a HPLC anion-exchange column; and vanadium(IV) cation was then eluted by 1 mM HNO₃, while vanadium(V) oxoacid anion was trapped on the column. After this separation, vanadium(V) was eluted as a cation from the column by 100 mM HNO₃. Vanadium was detected by ICP-AES. In this separation, about 15% of vanadium(V) interfered with vanadium(IV), and trace vanadium(IV) interfered with vanadium(V). This interference could be estimated by simple calculation based on stan-dard observations, and the speciation of vanadium(IV) and vanadium(V) was performed. The lower determination limit was 1 μg/mL, which is insufficient to speciate vanadium sampled by conventional sampling methods in a working environment. However, impu-rity of the other valent vanadium species in a vanadium(V) reagent can be determined by the present method, which should be valuable in precisely assessing the toxicities of vanadium species.