Phase equilibrium data are generated for clathrate hydrates of methane in THF aqueous solution for (0.040, 0.016, 0.010, and 0.005) mass fraction and with NaCl ((0.03, 0.05, and 0.10) mass fraction) in combination with THF ((0.010 and 0.005) mass fraction) for the methane hydrate system to study the effect of salt. The pressure-temperature curves for equilibrium points have been generated by employing an isochoric pressure-search method. The phase stability conditions were reported for a wide range of pressure (2.17 MPa to 6.43 MPa) and temperature (276.15 K to 297.70 K). Contending effects of THF and NaCl at various concentrations on the phase stability of the clathrate hydrate of methane have been studied. The inhibition effect of NaCl is limited by the promotion effect of THF for the clathrate hydrate of methane, even though there is a shift in the hydrate equilibrium curve toward the inhibition zone. The inhibition effect shown by salt is more enunciated at higher pressures compared to lower pressures. The promotion effect is found to decrease as the concentration of NaCl is increased. Moreover, the promotion effect of THF at a lower concentration is commendable on NaCl with higher concentration for methane hydrate formation. The values of heat of dissociation of hydrates for the (THF + CH4) system and the (THF + NaCl + CH4) system at different experimental pressure and temperature conditions are calculated using the Clausius-Clayperon equation for the obtained phase equilibrium data and reported. This study shows that the clathrate hydrates of methane in THF and in (THF + NaCl) aqueous system are anticipated to be more stable as compared to the hydrates of pure methane, thus promising their use for formation, storage, and transportation of the hydrates of natural gas in a real environment. © 2014 American Chemical Society.