The fatty acid compositions and total oil contents in achenes of 22 Cirsium taxa collected from different natural habitats in Turkey were investigated. The range of total fat in the taxa varied from 1.7% to 13.3%. The taxa contained palmitic (C16:0), stearic (C18:0), oleic (C18:1n-9), linoleic (C18:2n-6), and α-linolenic (C18:3n-3) acid. Polyunsaturated fatty acids had the highest level, ranging from 52.1% to 75.2% (C18:2n-6) and 0.5%-17.3% (C18:3n-3). Total saturated (6.9%-17.4%), monounsaturated (11.7%-28.9%), and polyunsaturated (57.4%-79.9%) fatty acids varied substantially, whereas total unsaturated fatty acids ranged from 70.6% to 91.3%. Considerable variation was observed (P<0.05) within each taxon for these fatty acids, especially α-linolenic acid (C18:3n-3). Fatty acid compositions of the 22 taxa were compared by cluster analysis (UPGMA) and principle component analysis (PCA) based on six major fatty acids. This is the first report on the lipid content and fatty acid composition of achenes of Cirsium taxa growing in different areas of Turkey. Fatty acid profiles, relative proportions and levels of fatty acids can be used as additional biochemical markers in the taxonomy of Cirsium.