The gastropod mollusc Cerithidea obtusa was examined for its lipids and fatty acids. The non-polar lipids identified were hydrocarbons, steryl esters, triglycerides, free fatty acids and sterols. The major phospholipid was phosphatidyl choline. The predominant fatty acids were myristic, palmitic, stearic, oleic, linolenic, arachidonic and eicosapentaenoic acids. Combinations of chromatographic techniques have been employed for the qualitative and quantitative determination of the lipids and fatty acids of C. obtusa. © 1986.