Aqueous samples were mixed with a dilute solution of hydrogen peroxide and exposed to ultraviolet radiation in a continuous flow system. The organosulfur compounds were oxidized to oxalate, carbon dioxide, and sulfate. Subsequently, the sulfate ion was separated from the other anions including oxalate by automated ion chromatography using anion columns, carbonate eluent, and conductivity detector. By comparing the sulfate concentrations before and after oxidation, the amount of organically bound sulfur could be calculated. This procedure has been successfully applied to the routine analysis of over 2000 swamp and terrestrial waters submitted by the Limnology Section, Water Resources Branch, Ontario Ministry of Environment and Energy.