Ultrasonic speeds of 4-aminobutyric acid in 0.0041, 0.0125 and 0.0207 mol.kg(-1) aqueous salbutamol sulphate (SBS) solutions are measured at 308.15, 313.15 and 318.15 K. Isentropic compressibility k(s), change in isentropic compressibility Delta k(s), relative change in isentropic compressibility ( Delta k(s) / k(s)(0)), apparent molal compressibility k(phi), limiting apparent molal compressibility k(phi)(0), transfer limiting apparent molal compressibility Delta k(phi)(0), hydration number n(H), pair and triplet interaction parameters k(AS), k(ASS) are estimated. The above parameters are used to interpret the solute-solute and solute-solvent interactions of 4-aminobutyric acid in the aqueous salbutamol sulphate solutions.