Seed fatty acids composition of Lathyrus nissolia L., Lathyrus hirsutus L., Pisum sativum L. var. arvense (L.) Poiret., Onobrychis montana DC. subsp. cadmea (Boiss.) P.W.Ball., Trigonella monantha C.A.Mey. subsp. monantha, Trigonella foenum-graceum L. were analyzed by gas chromatography of the methyl esters of their fatty acids. The fatty acid composition of the studied taxa were found as identical qualitatively, but some quantitative differences were determined in interspecific and intergenus level. The fatty acid composition of studied plants showed different saturated and unsaturated fatty acid concentrations. The major fatty acids were found to be linoleic acid (11.94-53.09%), linolenic acid (7.70-47.05%), oleic acid (0.00-28.01%), palmitic acid (12.40-26.14%) and stearic acid (2.82-10.25%); while other fatty acids were found in minor percentages. As a result, in this research we detected that all taxa had the higher total unsaturated fatty acid (UFA) (68.11-80.67%) than saturated fatty acid (SFA) (19.33-31.89%) amounts. The higgest UFA detected to Trigonella monantha subsp. monantha (80.67%), lowest to Onobrychis montana DC. subsp. cadmea (68.11%). In this study, palmitic and stearic acid were found in the major saturated fatty acids; while oleic, linoleic and linolenic acids were found to be the major unsaturated fatty acids. Chemotaxonomic implications of the components of the studied plant taxa are discussed and the main components could be used as a chemotaxonomical marker.