A universal Prediction method for Henry's constants of alkanes in alkane solvents has not been established. The present study proposes a universal method for the prediction of Henry's constants representing all of the data for alkane/alkane binaries in the literature. The method involves two universal constants and works at T-ri < 3, where T-ri denotes the reduced temperatures of the solute alkanes. One of the constants modifies the expression of the infinite-dilution activity coefficients for their application to simple fluids reflecting end-to-sphere molecular orientations, whereas the other represents the vapor pressures of hypothetical liquids defined above solute critical. The prediction method also satisfactorily predicts the Henry's constants of rare gases and liquids having spherical molecules, such as Ar, Kr, Xe, and M, in alkane solvents. Using the prediction method, the most reliable data of high-pressure vapor-liquid equilibrium for alkane/alkane binaries under dilute conditions in the literature were identified. (c) 2005 American Institute of Chemical Engineers.