Abstract The distribution of vanadium(IV) between sulphuric acid solutions and solutions of bis-(2-ethyl hexyl)-phosphoric acid (abbreviated as HDEHP or H 2A 2) in benzene and kerosene has been investigated as a function of the extractable metal ion, sulphate, acetate, nitrate and extractant concentrations, temperature and the nature of the diluents. The distribution coefficient has been found to increase with increasing concentration of the extractant, acetate, nitrate and temperature and with decreasing acidity and sulphate concentration. From the temperature dependence data, the apparent enthalphy change for the extraction reaction has been calculated to be ΔH = 4.74 kcal/mole. The molecular weight and the phosphorus-vanadium atom ratio of the solid complex have been found to be 2000 and 2:1 respectively. The mechanism of the extraction is discussed.