The first Raman optical activity spectra of glycosaminoglycans (GAGs) are reported and exhibited characteristic features specific to the major chemical differences in GAGs (N-, O-sulfation and N-acetylation). Furthermore, the lack of major features between 1050-1150 cm(-1) for heparin and N-acetyl heparin suggests that these molecules do not adopt strongly helical conformations in solution and indicate subtly different solution conformations.