Interaction between aspartic acid and D-glucose, D-galactose, and D-fructose has been studied by isothermal titration calorimetry, calorimetry of dissolution, and densimetry. It has been found that D-glucose and D-fructose form thermodynamically stable associates with aspartic acid, in contrast to D-galactose. The selectivity in the interaction of aspartic acid with monosaccharides is affected by their stereochemical structures.