An aqueous acetylation method was evaluated for the identification and quantification of simple phenolic compounds in oil sand extraction plant effluents from the Syncrude Canada Ltd plant . Water samples were acetylated by the addition of acetic anhydride and sodium bicarbonate and extracted into methylene chloride. The concentrations were analysed by gas chromatography and mass spectrometry. The method was successfully applied to the analysis of phenols and cresols in tailings pond water, drainage water, groundwater and surface water. Quantitative results for acetate derivatives were reproducible and interference from other constituents was minimal.