We studied the effect of ionic liquid, 1-butyl-3-methyl imidazolium chloride on thermodynamic and transport properties of aqueous lithium bromide solutions. In this work, densities, speed of sound and viscosity of these systems at 298.15, 303.15, 308.15, 313.15, and 318.15K have been measured. The apparent molar volume, isentropic compressibility, apparent isentropic compressibility and relative viscosity values have been evaluated from the experimental density, speed of sound and viscosity data. Redlich–Mayer equation has been applied for correlating the apparent molar volumes and apparent molar isentropic compressibility values in dilute region. Viscosity data in the whole concentration range were correlated to a semi-empirical equation. The viscosity B-coefficients were obtained by fitting viscosity data to Jones–Dole equation. It is well established that viscosity B-coefficient is a measure of solute–solvent interactions, and is directly dependent on the size, shape and charge of the solute molecules.