Liquid-liquid equilibrium (LLE) data for the Na2MoO4+ polyethylene glycol 4000 (PEG 4000) + H2O system were determined experimentally at T= (288.15, 298.15 and 308.15) K. Additionally, experimental data of density, sound velocity, refractive index and viscosity are also reported at T= (288.15, 298.15 and 308.15) K. The effect of temperature on the binodal curves and tie-lines was studied and it was found that an increasing in temperature caused the expansion of two-phase region. The extended UNIQUAC model and the Othmer-Tobias and Bancroft equations were used to correlate the experimental tie-line data obtaining a good representation of the equilibrium. Moreover, the Merchuk equation was used to correlate the binodal curves. A good agreement between experimental and correlated values of the tie-lines was obtained. (c) 2015 Elsevier B.V. All rights reserved.