Isothermal vapor-liquid equilibrium measurements of three binary systems, H2S + propane, H2S + n-butane, and H2S + n-pentane, have been performed with a static synthetic apparatus at low temperatures. The method of Barker has been implemented to determine the corresponding nonrandom two-liquid (NRTL) parameters and to calculate the liquid mole fractions. The results have been further used along with literature data to adjust binary interaction parameters of the Peng-Robinson equation of state. Good agreement with Dechema values has been found.