Liquid hydrocarbon oil and water have been produced from the liquefaction of cellulosic matter present in municipal solid wastes. The produced pyrolytic oil and water fraction seemed to be contaminated with considerable amounts of oxygen compounds as compared with fuels derived from a petroleum origin. The oxygen compounds included organic acids (fatty and naphthenic acids), phenols, and carbonyl compounds. These classes of oxygen compounds were extracted selectively from the pyrolytic oils and water using chemical extraction methods. Methyl esters of fatty acids and 2,4-dinitrophenylhydrazones of carbonyl compounds were identified by gas chromatography and thin layer chromatography, respectively. It was suggested that the identified oxygen compounds could be produced from the pyrolysis of volatiles (e.g., levoglucosane, which is the primary product of cellulose depolymerization) via different mechanistic pathways.