In this study, FT-IR, FAR-IR, and FT-Raman spectra of Furosemide were recorded between 4000 and 650 cm(-1), 700 and 150 cm(-1) and 4000 and 150 cm(-1) regions, respectively. In addition, the single crystal, X-ray structure is determined for this molecule. The X-ray analysis showed two alternative orientations; E and Z-form which formed dimer structure by O-H center dot center dot center dot O hydrogen bonds. The theoretical analysis of probable stable conformers of Furosemide was carried out by using DFT method with 6-31G(d,p) basis set while density functional theory (DFT/B3LYP) method with 6-31G(d,p), 6-31G(d) and Sadlej PVTZ as basis sets was used for quantum chemical calculations of geometrical structure and vibrational wavenumbers. Additionally, the anharmonic wavenumbers were calculated by using the same theory with 6-31G(d,p) basis set. A detailed interpretation of the infrared and Raman spectra of Furosemide was made based on total energy distribution (TED). Finally, probable donor-acceptor interactions of E and Z form of the molecule were examined by using NBO analysis. (C) 2012 Elsevier B.V. All rights reserved.