The apparent molar volumes, ΦV, of some α-amino acids in aqueous solutions and four various molalities potassium chloride solutions were determined from precise density measurements with a DMA 602 digital density meter at ordinary pressure and 298.15K. partial molar volumes, V °, have been also evaluted from the apparent molar volumes in various solute concentrations. these data have been used to calculate the partial molar volumes of transfer of amino acids from water to aqueous potassium chloride solutions and the contributions of the side-chain in amino acid to partialmolal volumes of amino acids in water and potassium chloride aqueous solutions respectively .the number of water molecules hydrated amino acid and volumetric interaction coeffcients were calculazted. the results indicate:the partial potassium chloride; 1:1 interactionbetween amino acid and KCl in solutions is dominant; the hydration number decresese with the increasing of potassium chloride molality. a qualitatived scussiom is given.

Key words: AMINO ACID, AQUEOUS SOLUTION, WATER, POTASSIUM CHLORIDE, VOLUMES, PARTIAL MOLAL VOLUME