Diffusion coefficients of linoleic acid methyl ester, Vitamin K-3 and indole in mixtures of carbon dioxide and n-hexane were measured at 313.2 K, and 16.0 and 25.0 MPa by using the Taylor dispersion method. It was found that the measured diffusion coefficients D-1m were well correlated by the Blanc's equation: D-1m =1/ X-2/D-12 + x(3)/D-13 where x(2) and x(3) are mole fractions of CO2 and n-hexane, and D-12 and D-13 are binary diffusion coefficients of the solutes in CO2 and n-hexane, respectively, measured at the same temperature and pressure. Other equations for D-1m as a function of temperature and solvent viscosity, were tested as a possible correlating equation.