The present work includes density and speed of sound measurements of cationic surfactant, dodecyltrimethylammonium bromide (DTAB), and anionic surfactant, sodium dodecylsulphate (SDS), in aqueous solutions of 0.01 mol.kg(-1) tetraalkylammonium-based ionic liquids (ILs) in the temperature range 293.15-318.15 K. The experimental data have been employed to evaluate volumetric and compressibility parameters viz. apparent molar volume (V-phi), isentropic compressibility (kappa(s)), apparent molar adiabatic compression (kappa(s,phi)), change in isentropic compressibility (Delta kappa(s)), and relative change in isentropic compressibility (Delta kappa(s)/kappa(o)). All these parameters yield qualitative information regarding the self-assembling behavior of the surfactant in the ternary (surfactant-water-IL) system. Adequate knowledge of these parameters for amphiphilic solutions in IL solvents is essentially required to clarify the nature of molecular interactions between the surfactant and solvent and to design new chemical and technological processes.