Density, sound velocity, and viscosity of 1-ethyl-3-methylimidazolium bromide, [Emim][Br], in aqueous solutions of tri-potassium phosphate with salt weight fractions (w(s) = 0 00, 0.10, 0 15, and 0 20) have been measured as a function of concentration of [Emim][Br] at atmospheric pressure and T = (298.15, 303 15, 308 15, 313.15, and 318 15) K The apparent molar volume. isentropic compressibility, apparent isentropic compressibility, and relative viscosity values have been evaluated from the experimental data The partial molar volume and isentropic compressibility at infinite dilution, and viscosity B-coefficient obtained from these data have been used to calculate the corresponding transfer parameters for the studied IL from water to the aqueous tri-potassium phosphate solutions Also, an empirical equation was satisfactorily used to correlate the experimental viscosity data. (C) 2010 Elsevier Ltd All rights reserved.