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 ΔK S , relative change in isentropic compressibility (ΔK S /K 0 S ), apparent molal compressibility K ø , limiting apparent molal compressibility K 0 ø , transfer limiting apparent molal compressibility δK 0 ø , 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.