Viscosity coefficients of (L-alanine-, L-proline, L-valine, L-leucine + 2.0 M aqueous KCL/KNO3) solutions have been determined as a function of amino acid concentration at different temperatures: (298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K. The trends of variation of viscosity values with increase in the concentration of L-alanine, L-proline, L-valine, and L-leucine in 2.0 M aqueous KCl and 2.0 M aqueous KNO3 solutions, and temperature have been ascribed to the solute-solvent interactions operative in the solutions. (C) 2008 Elsevier Ltd. All rights reserved.