Due to its ability to analyze macromolecules, as well as polar and thermally labile low molecular weight compounds, mass spectrometry has become a very important tool in bioanalysis in recent years. The Life Sciences Mass Spectrometry Laboratory (LSMS) at the School of Pharmaceutical Sciences, University of Geneva, opened on April 1st, 2002. Its work is focused on the development and application of mass spectrometry for the qualitative and quantitative analysis of low molecular compounds and macromolecules present in biological fluids, tissues, organisms or cells. The instruments used for the research include: single quadrupole, triple quadrupole and hybrid MS instruments such as triple quadrupole linear ion traps; equipped with electrospray, nanoelectrospray, atmospheric pressure chemical ionization and matrix-assisted laser desorption.