The objective of this work is to obtain the basic data for the selective extraction of unsaturated fatty acids from soybean oil. a model mixture containing oleic, linoleic, and linolenic acid supported on silica gel was extracted with supercritical carbon dioxide and supercritical carbon dioxide plus an entrainer. It was found that benzene and ethylacetate were promising entrainers for separating oleic acid and the effect of these entrainers was in accordance with the result predicted by GC affinity test.