The photolysis of water vapor with carbon monoxide at 1849 A yields alcohols, aldehydes and organic acids, with an overall quantum yield of 3.3 x 10(-2). This rather high quantum yield could have led to a contribution of approximately 10(11) organic molecules cm-2 sec-1 to the pool of organic material on the primitive Earth. The reactions are initiated by the photolysis of water molecules and the resulting hydrogen atoms reduce the carbon monoxide to a variety of one and two carbon compounds. The organic molecules are dissolved in water and thus escape destruction by photolysis. Photolysis of water vapor with carbon dioxide did not yield organic compounds under these conditions.