Isobaric vapor-liquid equilibrium data at 101.33 kPa are reported for binary systems formed by N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF) with benzene, heptane, hexane, or cyclohexane, Data reduction based on the Van Laar, Wilson, NRTL, and UNIQUAC models provides It correlation for the liquid-phase activity coefficients. All the systems, except for the ones formed with benzene, are strongly nonideal, yielding two phases at law temperatures.