The system CH3OH-HCl is a non-aqueous, extremely corrosive electrolyte system. The salient characteristic of the system is its strong reactivity. The vapour pressure of the system has been determined with a static method at low pressure. The vapour pressures of 22 samples in the concentration range 1.7-33.3 mol% HCl have been measured. The data were obtained over a temperature range from about - 10 degrees C up to detectable formation of methyl chloride. The paper also presents the measurement of intermediate heats of dilution for the system CH3OH-HCl at 24.8 degrees C.