The densities of binary liquid mixtures of dimethyl sulfoxide and gamma-butyrolactone at (293.15, 298.15, 303.15 and 313.15) K and viscosity at T= 298.15 K have been measured at atmospheric pressure over the entire range of concentration. From these data the excess molar volumes V-E at (293.15, 298.15, 303.15 and 313.15) K and the viscosity deviation, the excess entropy, and the excess Gibbs energy of activation for viscous flow at T= 298.15 K have been determined. These data were mathematically represented by the Redlich-Kister polynomial. Partial and apparent molar volumes have been calculated for better understanding of the interactions in the binary systems. The obtained data indicate the lack of specific interactions between unlike molecules, which seem to be a little weaker as compared to the interactions in pure solvents. (C) 2017 Elsevier Ltd.