The phase behavior of the carbon dioxide-hydrogen sulphide-methane system, previously reported at a temperature of 100°.F.(1), has been investigated at pressures of 400, 1000, and 1600 lb./in.2abs. at 40°F. and at pressures of 1000, 1330 and 1600 lb./in.2abs. at 160°F. Correlation of the experimental data is based upon equilibrium ratios calculated for the individual components, Equilibrium ratios were found to be a function of system composition, temperature, and pressure. Deviation of the liquid phase from ideal solution behavior, as indicated by calculated activity coefficient ratios, is, in general, most dependent upon system composition at the higher pressures and lower temperatures.