New vapor-liquid equilibrium (VLE) data for 1-propanethiol + 1-butanethiol + CH4 ternary system is reported. Measurements were performed at three different temperatures (303, 336, and 368 K), and the pressure ranged from 1 to 9 MPa. The total system pressure was maintained by CH4. The inlet mole fraction of 1-propanethiol (x = 5.43 x 10(-1)) and 1-butanethiol (x = 4.56 x 10(-1)) in the liquid phase were same in all experiments. A static analytic method was used for performing phase equilibrium measurements. The new VLE data have been modeled successfully with cubic-plus-association (CPA) equation of state.