Lepidium sativumis a key species in Sudanese system of medicine where it is used traditionally against a wide range of diseases. The plant contains vitamins A and C beside some minerals. It also contains folic acid; protein; leucine; glutamic acid and methionin. Seeds contains some alkaloids, beside carotene, riboflavan, uric acid, phosphorus, thiamine and niacin. This study was designed to investigate the major flavonoid of Lepidium sativum. The flavonoids were extracted with ethanol and the crude extract was purified by thin layer chromatography where a pure flavone was isolated. The structure of this flavone has been partially characterized by some spectral tools (UV and ¹HNMR).