Flavonoids identification,total fiavonoids content and antioxidant activity of the extracts from the leaves as well as flowers of cassia angostifolia were determined.Five different extraction techiques were used for the extraction of flavonoids from leaves and flowers.Total flavonoids contents (TFC)in the extracts were determined by UV-visible spectrophotometry.Individual flavonoids were identified and quantified by high-performance liquid cromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry(HPLC-PDA-ESI-MS).It has been examined that aqueous ethanol fractions of C.angostifolia flowers and leaves are highly rich in flavonoids and microwave extraction is the best method for the extraction of individual flavonoids constituents(1-9)as well as total flavonoid contents.It was also found that compound 8 was absent in the leaves and compounds 2 and 5 could not be indentified.The extracts of C.angostifolia flowers and leaves show strong antioxidant activity.