Vibrational spectroscopies (VS), INFRARED SPECTROSCOPY and RAMAN SPECTROSCOPY, are well-established techniques for exploring the chemical composition of samples. VS are based on the molecular vibrations and give a spectral signature also called “molecular fingerprint” characteristic of the studied material. Recent advances in these techniques have rendered them faster, more sensitive, and easier to use. This chapter describes their application to characterize the main glycosaminoglycans—without any sample destruction or degradation. Nowadays, the use of multivariate statistical analysis for analyzing spectral data allows to extract rapidly the discriminant spectral information from large data sets. The combination of VS and this type of data analysis is also discussed in this chapter.