Fish gills of Thunnus albacares have been chosen as a unique source of glycosaminoglycans (GAGs) in this study. Chemical and physical characterization were carried out by ATR -FTIR spectroscopy, DEAE -Cellulose anion exchange chromatography, SAX -HPLC, and NMR techniques to determine the nature of GAG isolated. The results showed that the isolated GAGs (8.5mg/g yield) were mostly Chondroitin sulphate (CS) type. SAX HPLC chromatogram of isolated GAG and CS A standard showed comparable peaks A at 4.9, B at 7.8 and C at 9.99 min. FTIR spectra, IR (KBr) υ max in cm -1 presented characteristic peaks of -CONH vibration of amide group, coupling of C-O stretching vibration, S=O stretching vibrations and -C-O-S molecules confirmed the presence of CS type GAG in T. albacaresgills. 1 H NMR spectra in D2Oalso revealed the presence of CS moiety. All these results substantiate T. albacares gills as an excellent source of CS type GAG.