This project involves new solubility measurements of the water distribution in vapor of the methane/water binary system near the hydrate formation conditions. Isothermal vapor-liquid and vapor-hydrate equilibrium data of the vapor phase for the methane/water binary system were measured at 283.08, 288.11, 293.11, 298.11, 303.12, 308.11, 313.12 and 318.12 K and pressures up to 35 MPa. In this work a static-analytic apparatus taking advantage of a pneumatic capillary sampler (Rolsi(TM), Armines' patent) developed in the Cenerg/TEP laboratory is combined with an exponential dilutor. The results are compared with literature data. The eight sets of isothermal P, gamma data are represented with the Peng-Robinson equation of state (PR EoS) using the Trebble-Bishnoi alpha function, the classical mixing rules for the vapor phase and a Henry's law approach to treat the aqueous phase. The water phase distribution at hydrate forming conditions was calculated by using the Van der Waals and Platteeuw Model. (C) 2003 Elsevier B.V. All rights reserved.