A method for determining the shale oil mist content in retort gas is described here. The studies necessary to develop the method were made on the pilot plant gas combustion retort at Rifle, Colo. All oil mist sampling was done at the inlet and outlet gas lines of the electrostatic precipitator, the last unit in the oil recovery train of the retort. It is proposed that this method of determining oil mist may be used with some minor modification of the mist collecting equipment at any point in the oil recovery and gas handling system of this type of oil shale retort.