Density and viscosity measurements are reported for aqueous solutions of the drugs like Metformin hydrochloride (MH), Ranitidine hydrochloride (RH) and Tramadol hydrochloride (TH) at different temperatures T = (288.15, 298.15, and 308.15) K within the concentration range (0 to 0.15) mol.kg (1). The density and viscosity data are used to obtain apparent molar volume of solute (phi(V)) and relative viscosity (eta(r)) of aqueous solutions at different temperatures. The limiting apparent molar volume of solute (phi(0)(V)), limiting apparent molar expansivity (phi(0)(E)), thermal expansion coefficient (alpha*), hydration number (n(h)), Jones-Dole equation viscosity A and B coefficients, experimental slope (S-V) at different temperatures, and temperature coefficient of B i.e. (dB/dT) at T = 298.15 K were also obtained. The results obtained have been interpreted in terms of solute-solvent and solute-solute interactions and structure making/breaking ability of solute in the aqueous solution. (C) 2012 Elsevier Ltd. All rights reserved.