Isobaric vapor-liquid equilibria (VLE) were measured for four binary systems containing tetrahydrofuran (THF): THF + water, and three different mixtures of THF + n-alkane (n-pentane, n-hexane, and n-heptane). Measurements were conducted at pressures in the range 40.0-101.3 kPa using a simple, automatic apparatus developed in our laboratory. From the experimental VLE data it was confirmed that the THF + water and THF + n-hexane systems formed minimum-boiling-point azeotropes, whereas the THF + n-pentane and THF + n-heptane systems were non-azeotropic mixtures. Non-random two-liquid (NRTL) parameters were also determined on the basis of the experimental VLE data.