The equation of state for fluids containing chain-like molecules presented in previous work has been extended to mixtures by using the van der Waals one fluid theory (vdW1) for the energy parameter responsible for interactions between segments. With an adjustable binary interaction parameter, satisfactory fit for experimental pVT data of binary liquid mixtures including polymer blends, as well as binary vapor-liquid-equilibria data of volatile systems and polymer solutions can be obtained. The potential application for liquid-liquid equilibria is also discussed.