Densities, p, ultrasonic speeds, u, and viscosities, eta, of aqueous-1,4-butanediol (20% and 40% w/w of 1,4-butanediol) and of solutions of glycine (Gly), DL-alanine (Ala), and L-valine (Val) in aqueous-1,4-butanediol were measured at T = (298.15, 303.15, 308.15, 313.15, and 318.15) K. From these experimental results, apparent molar volume, V-phi, limiting apparent molar volume, V-phi and the slope, S-k, apparent molar compressibility, kappa(phi) limiting apparent molar compressibility, kappa(o)(phi), and the slope, S-k, transfer volume, V-phi,tr(o), Falkenhagen coefficient, A,Jones-Dole coefficient, B, free energies of activation of viscous flow per mole of solvent, Delta mu(o#)(1) and per mole of solute, Delta mu(o#)(2) were calculated. The results are interpreted from the point of view of solute-solvent and solute-solute interactions in these systems. It has been observed that there exist strong solute-solvent interactions in these systems, which increase with rise in temperature. For the amino acids studied, the values of V; follow the order: Gly < Ala < Val, indicating that the increased hydrophobic/non-polar character of the side chain of these amino acids causes a reduction in electrostriction at the terminal charged groups. These amino acids act as structure-breakers in aqueous-1,4-butanediol solvents. The thermodynamics of viscous flow has also been discussed. (C) 2008 Elsevier Ltd. All rights reserved.