Ultrasonic velocity, density and viscosity of solutions of some derivatives of sulphonamides in dimethylformamide (DMF) were measured at 35 degreesC. From these experimental data, various acoustical properties such as specific impedance (Z), isentropic compressibility (K-s), Rao's molar sound function (R-m), the Van der Waals constant (b), molar compressibility (W), intermolecular free length (L-f), relaxation strength (r), free volume (V-f), relative association (R-A), internal pressure (pi), apparent molar volume (phi(v)), apparent molar compressibility (phi(K)), etc. were calculated. The results are interpreted in terms of molecular interactions occurring in the solutions.