The enthalpies of solution of L-alpha-isoleucine, L-alpha-cysteine, L-alpha-aspartic acid, and L-alpha-glutamic acid have been measured in aqueous sodium chloride solutions at 298.15 K. From the obtained experimental results the standard dissolution enthalpies of amino acids in aqueous NaCl solutions have been determined. These data were used to calculate of the heterogeneous enthalpic pair interaction coefficients based on McMillan-Mayer's theory. These values were interpreted in the terms of the hydrophobic or hydrophilic effects of the side chains of amino acids on their interactions with dissociated sodium chloride in water.