The dilution enthalpies of four chiral diols, namely (2S,4S)-(+)-2,4-pentanediol vs (2R,412)-(-)-2,4-pentanediol and (2S,5S)-(+)-2,5-hexanediol vs (2R,512)-(-)-2,5-hexanediol in dimethylsulfoxide (DMSO) + water mixtures at 298.15 K have been determined respectively, using isothermal titration calorimeter (ITC). On the basis of the McMillan-Mayer theory, homochiral enthalpic pairwise interaction coefficients (h(xx)) of the four diols in the mixed solvents of various mass fractions (w=0-0.3) have been calculated. It is found amazedly that across the whole studied composition range of mixed solvent values of h(xx) for S-enantiomer are almost higher than R-enantiomer for each diol. The results are discussed from the point of view of solute-solute interaction and solute-solvent interaction accompanied by chiral discrimination effect. The variations of h(xx) with w for the four chiral diols depend largely on the competition equilibrium between hydrophobic-hydrophobic, hydrophilic-hydrophilic and hydrophobic-hydrophilic interactions in the ternary solution systems. (C) 2012 Elsevier B.V. All rights reserved.