A phytochemical study was carried out on Ononis natrix seeds (Fabaceae), plant largely distributed in SW of Morocco. Phytochemical screening indicated the presence of catechic tannins, saponins, coumarins and terpens. The GC analysis of the methyl esters of fatty acids showed that linoleic and linolenic acids are the most prominent constituents of the oil respectively 33% and 27%. While TLC analysis showed that the oil contains mainly triglycerides and phospholipids. Ononis natrix seeds are rich in proanthocyanidins (prodelphinidin and procyanidin), and flavonics aglycones, the most important are quercetin, kaempferol, isorhamnetin, nevadensin and penta-hydroxy-5,6,7,3′,4′ methoxy-3 flavon.