The removal of dissolved oxygen (DO) from water was studied using a silicone rubber hollow-fiber membrane module. Dissolved oxygen in water was effectively reduced by the vacuum degassing or pervaporation process through a non-porous membrane. The controlling transport property, gas permeability through the membrane, was independently measured by a method using a differential transformer. A gas-phase driving force model was presented based on the permeabilities of the permeates through the hollow-fiber. Experimental results of the oxygen removal from water were compared with the model calculations. The present model proved to explain the effects of the pressure condition and the operation mode on the removal of oxygen from water. Although the liquid-phase mass transfer resistance was shown to have a large effect on the removal performance of the membrane module, the membrane permeation step controlled the mass transfer during Vacuum degassing.