The use of vibrational spectroscopy, especially the Fourier Transform Infrared (FTIR) and Raman methods, for the structural and functional characterisation of deoxyribonucleic acid (DNA) is covered in detail in this chapter. The chapter emphasizes the non-destructive, labelfree benefits of these methods while pointing out how sensitive they are to structural transitions (like helix-coil melting), conformational states (like A-, B-, and Z-DNA), and environmental variables like pH, temperature, and moisture. In order to accurately analyze structural integrity and molecular interactions, detailed vibrational band assignments are investigated for the phosphate backbone, base pairs, and sugar moieties of DNA. Along with reviewing the spectroscopic characteristics of single-versus double-stranded DNA, the chapter additionally examines at how external factors, such as medications, metal ions, proteins, and protective ligands, affect the stability and conformation of DNA. A special importance is given to the diagnostic potential of Raman and Surface-Enhanced Raman Scattering (SERS) in detecting epigenetic changes, including DNA methylation. The practical difficulties and limitations of existing approaches are critically assessed, along with concepts for incorporating vibrational spectroscopy into forensic and biological applications. All of these observations support the critical role that Raman and FTIR spectroscopy play in contemporary nucleic acid research and diagnostics.