The viscosities of some mineral salt viz.; potassium chloride, potassium nitrate, magnesium chloride, magnesium nitrate, at different concentrations have been determined in water and in binary aqueous solution of sodiumdodecyl sulfate (SDS) (0.007 mol · kg −1 and 0.01 mol · kg −1) at different temperatures. The data have been analyzed using Jones–Dole equation and the derivative parameters B and A have been interpreted in terms of ion–solvent and ion–ion interactions respectively. The change of Gibbs free energy of activation ( Δ G η ≠ ) , enthalpy of activation ( Δ H η ≠ ) , and entropy of activation ( Δ S η ≠ ) for viscous flow of the solutions were calculated using Eyring equation, which depicts the mechanism of viscous flow. The structure making/breaking nature of the studied electrolytes has been discussed in the light of first derivative of B-coefficient (d B/d T) over temperatures. Potassium chloride and potassium nitrate acts as structure breaker in water where as all the salts are structure makers in aqueous SDS solutions, i.e. the postmicellar and pre-micellar regions.