The refractive index (n(D)) and density (rho) values of the poly(ethylene glycol) (PEG) 1500 + dipotassium tartrate + water ternary system and physical properties of PEG 1500 + water and dipotassium tartrate + water binary solutions have been measured at 298.15 K and atmospheric pressure. Moreover, the refractive index deviation (Delta(nD)), viscosity deviation (Delta eta), apparent specific volume (V-phi), excess molar volume (V-E), and excess Gibbs energy of activation for viscous flow (Delta G(double dagger E)) were calculated from the experimental measurements to analyze the behavior of the binary solutions and the refractive index deviation (Delta(nD)) and excess molar volume (V-E) of the ternary solution. These results were fitted to Redlich-Kister polynomial and Cibulka Equations to estimate the interaction parameters. Adjustments were made to the refractive index and density to obtain a third-order polynomial expansion model and a second-order equation, respectively. The intermolecular interactions between the mixing components were demonstrated by the obtained data from the calculated functions.